[maven-release-plugin] prepare release avaje-ebeanorm-6.5.1

This adds default implementations for register,filter, prepare and log of the change sets.

.gitignore

@@ -9,6 +9,7 @@ logs/
 log/
 /db
 /mydb.db
+!src/test/ddl-review/*.sql
 
 
 # Intellij project files

pom.xml

@@ -9,7 +9,7 @@
 
   <groupId>org.avaje.ebeanorm</groupId>
   <artifactId>avaje-ebeanorm</artifactId>
-  <version>6.1.1</version>
+  <version>6.5.1</version>
   <packaging>jar</packaging>
 
   <name>avaje-ebeanorm</name>
@@ -163,31 +163,11 @@
     </dependency>
 
     <dependency>
-      <groupId>junit</groupId>
-      <artifactId>junit</artifactId>
-      <version>4.11</version>
-      <scope>test</scope>
-    </dependency>
-    
-    <dependency>
-      <groupId>org.hamcrest</groupId>
-      <artifactId>hamcrest-integration</artifactId>
-      <version>1.3</version>
-      <scope>test</scope>
-    </dependency>    
-
-    <dependency>
-      <groupId>org.mockito</groupId>
-      <artifactId>mockito-core</artifactId>
-      <version>1.9.5</version>
-      <scope>test</scope>
-    </dependency>
-
-    <dependency>
-      <groupId>ch.qos.logback</groupId>
-      <artifactId>logback-classic</artifactId>
-      <version>1.0.9</version>
+      <groupId>org.avaje.composite</groupId>
+      <artifactId>avaje-composite-testing</artifactId>
+      <version>1.1</version>
       <scope>test</scope>
+      <type>pom</type>
     </dependency>
 
     <dependency>

src/main/java/com/avaje/ebean/BeanState.java

@@ -33,6 +33,11 @@ public interface BeanState {
    */
   boolean isDirty();
 
+  /**
+   * This can be called with true to disable lazy loading on the bean.
+   */
+  void setDisableLazyLoad(boolean disableLazyLoading);
+
   /**
    * For partially populated beans returns the properties that are loaded on the
    * bean.

src/main/java/com/avaje/ebean/CallableSql.java

@@ -80,7 +80,7 @@ public interface CallableSql {
   /**
    * Return the label that is put into the transaction log.
    */
-  public String getLabel();
+  String getLabel();
 
   /**
    * Set the label that is put in the transaction log.

src/main/java/com/avaje/ebean/DRawSqlColumnsParser.java

@@ -80,17 +80,16 @@ final class DRawSqlColumnsParser {
     return new ColumnMapping.Column(indexPos++, sb.toString(), split[split.length - 1]);
   }
 
-  private int nextComma() {
+  private void nextComma() {
     boolean inQuote = false;
     while (pos < end) {
       char c = sqlSelect.charAt(pos);
       if (c == '\'') {
         inQuote = !inQuote;
       } else if (!inQuote && c == ',') {
-        return pos;
+        return;
       }
       pos++;
     }
-    return pos;
   }
 }

src/main/java/com/avaje/ebean/DRawSqlParser.java

@@ -24,7 +24,7 @@ class DRawSqlParser {
   private int placeHolderAndWhere;
   private int placeHolderHaving;
   private int placeHolderAndHaving;
-  private boolean hasPlaceHolders;
+  private final boolean hasPlaceHolders;
 
   private int selectPos = -1;
   private int distinctPos = -1;
@@ -98,19 +98,7 @@ class DRawSqlParser {
   }
 
   private boolean hasPlaceHolders() {
-    if (placeHolderWhere > -1) {
-      return true;
-    }
-    if (placeHolderAndWhere > -1) {
-      return true;
-    }
-    if (placeHolderHaving > -1) {
-      return true;
-    }
-    if (placeHolderAndHaving > -1) {
-      return true;
-    }
-    return false;
+    return placeHolderWhere > -1 || placeHolderAndWhere > -1 || placeHolderHaving > -1 || placeHolderAndHaving > -1;
   }
 
   /**

src/main/java/com/avaje/ebean/Ebean.java

@@ -168,9 +168,9 @@ public final class Ebean {
             defaultServer = getWithCreate(defaultName.trim());
           }
         }
-      } catch (RuntimeException e) {
+      } catch (Throwable e) {
         logger.error("Error trying to create the default EbeanServer", e);
-        throw e;
+        throw new RuntimeException(e);
       }
     }
 

src/main/java/com/avaje/ebean/EbeanServer.java

@@ -1,21 +1,21 @@
 package com.avaje.ebean;
 
-import java.util.Collection;
-import java.util.List;
-import java.util.Map;
-import java.util.Set;
-
-import javax.persistence.OptimisticLockException;
-import javax.persistence.PersistenceException;
-
 import com.avaje.ebean.annotation.CacheStrategy;
 import com.avaje.ebean.cache.ServerCacheManager;
 import com.avaje.ebean.config.ServerConfig;
 import com.avaje.ebean.meta.MetaInfoManager;
+import com.avaje.ebean.plugin.SpiServer;
 import com.avaje.ebean.text.csv.CsvReader;
 import com.avaje.ebean.text.json.JsonContext;
 import org.jetbrains.annotations.Nullable;
 
+import javax.persistence.OptimisticLockException;
+import javax.persistence.PersistenceException;
+import java.util.Collection;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+
 /**
  * Provides the API for fetching and saving beans to a particular DataSource.
  * <p>
@@ -128,6 +128,11 @@ public interface EbeanServer {
    */
   MetaInfoManager getMetaInfoManager();
 
+  /**
+   * Return the extended API intended for use by plugins.
+   */
+  SpiServer getPluginApi();
+
   /**
    * Return the BeanState for a given entity bean.
    * <p>
@@ -148,7 +153,7 @@ public interface EbeanServer {
    * difference comparison.
    * </p>
    */
-  Map<String, ValuePair> diff(Object a, Object b);
+  Map<String, ValuePair> diff(Object newBean, Object oldBean);
 
   /**
    * Create a new instance of T that is an EntityBean.
@@ -904,6 +909,15 @@ public interface EbeanServer {
    */
   <T> void findEachWhile(Query<T> query, QueryEachWhileConsumer<T> consumer, Transaction transaction);
 
+  /**
+   * Return versions of a @History entity bean.
+   * <p>
+   *   Generally this query is expected to be a find by id or unique predicates query.
+   *   It will execute the query against the history returning the versions of the bean.
+   * </p>
+   */
+  <T> List<Version<T>> findVersions(Query<T> query, Transaction transaction);
+
   /**
    * Execute a query returning a list of beans.
    * <p>
@@ -1099,6 +1113,21 @@ public interface EbeanServer {
   @Nullable
   <T> T findUnique(Query<T> query, Transaction transaction);
 
+  /**
+   * Execute as a delete query deleting the 'root level' beans that match the predicates
+   * in the query.
+   * <p>
+   * Note that if the query includes joins then the generated delete statement may not be
+   * optimal depending on the database platform.
+   * </p>
+   *
+   * @param query       the query used for the delete
+   * @param transaction the transaction to use (can be null)
+   * @param <T>         the type of entity bean to fetch.
+   * @return the number of beans/rows that were deleted
+   */
+  <T> int delete(Query<T> query, Transaction transaction);
+
   /**
    * Execute the sql query returning a list of MapBean.
    * <p>
@@ -1196,7 +1225,6 @@ public interface EbeanServer {
    *   public class Order { ...
    *
    * 	   @OneToMany(cascade=CascadeType.ALL, mappedBy="order")
-   * 	   @JoinColumn(name="order_id")
    * 	   List<OrderDetail> details;
    * 	   ...
    *   }
@@ -1226,9 +1254,9 @@ public interface EbeanServer {
   void delete(Object bean) throws OptimisticLockException;
 
   /**
-   * Delete all the beans in the collection.
+   * Delete the bean with an explicit transaction.
    */
-  int deleteAll(Collection<?> beans) throws OptimisticLockException;
+  void delete(Object bean, Transaction transaction) throws OptimisticLockException;
 
   /**
    * Delete the bean given its type and id.
@@ -1240,6 +1268,16 @@ public interface EbeanServer {
    */
   int delete(Class<?> beanType, Object id, Transaction transaction);
 
+  /**
+   * Delete all the beans in the collection.
+   */
+  int deleteAll(Collection<?> beans) throws OptimisticLockException;
+
+  /**
+   * Delete all the beans in the collection using an explicit transaction.
+   */
+  int deleteAll(Collection<?> beans, Transaction transaction) throws OptimisticLockException;
+
   /**
    * Delete several beans given their type and id values.
    */
@@ -1251,11 +1289,6 @@ public interface EbeanServer {
    */
   void deleteAll(Class<?> beanType, Collection<?> ids, Transaction transaction);
 
-  /**
-   * Delete the bean with an explicit transaction.
-   */
-  void delete(Object bean, Transaction transaction) throws OptimisticLockException;
-
   /**
    * Execute a Sql Update Delete or Insert statement. This returns the number of
    * rows that where updated, deleted or inserted. If is executed in batch then

src/main/java/com/avaje/ebean/ExpressionFactory.java

@@ -169,7 +169,22 @@ public interface ExpressionFactory {
    * In - property has a value in the collection of values.
    */
   Expression in(String propertyName, Collection<?> values);
-  
+
+  /**
+   * Not In - property has a value in the array of values.
+   */
+  Expression notIn(String propertyName, Object[] values);
+
+  /**
+   * Not In - property has a value in the collection of values.
+   */
+  Expression notIn(String propertyName, Collection<?> values);
+
+  /**
+   * Not In - using a subQuery.
+   */
+  Expression notIn(String propertyName, Query<?> subQuery);
+
   /**
    * Exists expression
    */

src/main/java/com/avaje/ebean/ExpressionList.java

@@ -4,6 +4,7 @@ import com.avaje.ebean.text.PathProperties;
 import org.jetbrains.annotations.Nullable;
 
 import java.io.Serializable;
+import java.sql.Timestamp;
 import java.util.Collection;
 import java.util.List;
 import java.util.Map;
@@ -95,6 +96,29 @@ public interface ExpressionList<T> extends Serializable {
    */
   Query<T> apply(PathProperties pathProperties);
 
+  /**
+   * Perform an 'As of' query using history tables to return the object graph
+   * as of a time in the past.
+   * <p>
+   *   To perform this query the DB must have underlying history tables.
+   * </p>
+   *
+   * @param asOf the date time in the past at which you want to view the data
+   */
+  Query<T> asOf(Timestamp asOf);
+
+  /**
+   * Execute as a delete query deleting the 'root level' beans that match the predicates
+   * in the query.
+   * <p>
+   * Note that if the query includes joins then the generated delete statement may not be
+   * optimal depending on the database platform.
+   * </p>
+   *
+   * @return the number of beans/rows that were deleted.
+   */
+  int delete();
+
   /**
    * Execute the query iterating over the results.
    * 
@@ -223,6 +247,24 @@ public interface ExpressionList<T> extends Serializable {
    */
   PagedList<T> findPagedList(int pageIndex, int pageSize);
 
+  /**
+   * Return versions of a @History entity bean.
+   * <p>
+   *   Generally this query is expected to be a find by id or unique predicates query.
+   *   It will execute the query against the history returning the versions of the bean.
+   * </p>
+   */
+  List<Version<T>> findVersions();
+
+  /**
+   * Return versions of a @History entity bean between the 2 timestamps.
+   * <p>
+   *   Generally this query is expected to be a find by id or unique predicates query.
+   *   It will execute the query against the history returning the versions of the bean.
+   * </p>
+   */
+  List<Version<T>> findVersionsBetween(Timestamp start, Timestamp end);
+
   /**
    * Add some filter predicate expressions to the many property.
    */
@@ -236,6 +278,24 @@ public interface ExpressionList<T> extends Serializable {
    */
   Query<T> select(String properties);
 
+  /**
+   * Set whether this query uses DISTINCT.
+   * <p>
+   * The select() clause MUST be specified when setDistinct(true) is set. The reason for this is that
+   * generally ORM queries include the "id" property and this doesn't make sense for distinct queries.
+   * </p>
+   * <pre>{@code
+   *
+   *   List<Customer> customers =
+   *       Ebean.find(Customer.class)
+   *          .setDistinct(true)
+   *          .select("name")     // only select the customer name
+   *          .findList();
+   *
+   * }</pre>
+   */
+  Query<T> setDistinct(boolean distinct);
+
   /**
    * Set the first row to fetch.
    * 
@@ -467,7 +527,22 @@ public interface ExpressionList<T> extends Serializable {
    * In - property has a value in the collection of values.
    */
   ExpressionList<T> in(String propertyName, Collection<?> values);
-  
+
+  /**
+   * Not In - property has a value in the array of values.
+   */
+  ExpressionList<T> notIn(String propertyName, Object... values);
+
+  /**
+   * Not In - property has a value in the collection of values.
+   */
+  ExpressionList<T> notIn(String propertyName, Collection<?> values);
+
+  /**
+   * Not In - using a subQuery.
+   */
+  ExpressionList<T> notIn(String propertyName, Query<?> subQuery);
+
   /**
    * Exists expression
    */

src/main/java/com/avaje/ebean/Finder.java

@@ -0,0 +1,167 @@
+package com.avaje.ebean;
+
+import org.jetbrains.annotations.Nullable;
+
+import java.util.List;
+
+/**
+ * Intended to be used as a base class for 'Finder' implementations that can then
+ * be injected or used as public static fields on the associated entity bean.
+ * <p>
+ * These 'finders' are a place to organise all the finder methods for that bean type
+ * and specific finder methods are expected to be added (find by unique properties etc).
+ * </p>
+ *
+ * <h3>Testing</h3>
+ * <p>
+ *   For testing the mocki-ebean project has the ability to replace the finder implementation
+ *
+ * </p>
+ * <pre>{@code
+ *
+ * public class CustomerFinder extends Finder<Customer> {
+ *
+ *   public CustomerFinder() {
+ *     super(Customer.class);
+ *   }
+ *
+ *   // Add your customer finder methods ...
+ *
+ *   public Customer byName(String name) {
+ *     return query().eq("name", name).findUnique();
+ *   }
+ *
+ *   public List<Customer> findNew() {
+ *     return query()
+ *       .eq("status", Customer.Status.NEW)
+ *       .orderBy("name")
+ *       .findList()
+ *   }
+ * }
+ *
+ * @Entity
+ * public class Customer extends BaseModel {
+ *
+ *   public static final CustomerFinder find = new CustomerFinder();
+ *   ...
+ *
+ * }</pre>
+ */
+public class Finder<I, T> {
+
+  /**
+   * The entity bean type.
+   */
+  private final Class<T> type;
+
+  /**
+   * The name of the EbeanServer, null for the default server.
+   */
+  private final String serverName;
+
+  /**
+   * Create with the type of the entity bean.
+   *
+   * <pre>{@code
+   *
+   * public class CustomerFinder extends Finder<Customer> {
+   *
+   *   public CustomerFinder() {
+   *     super(Customer.class);
+   *   }
+   *
+   *   // ... add extra customer specific finder methods
+   * }
+   *
+   * @Entity
+   * public class Customer extends BaseModel {
+   *
+   *   public static final CustomerFinder find = new CustomerFinder();
+   *   ...
+   *
+   * }</pre>
+   */
+  public Finder(Class<T> type) {
+    this.type = type;
+    this.serverName = null;
+  }
+
+  /**
+   * Create with the type of the entity bean and specific server name.
+   */
+  public Finder(Class<T> type, String serverName) {
+    this.type = type;
+    this.serverName = serverName;
+  }
+
+  /**
+   * Return the underlying 'default' EbeanServer.
+   *
+   * <p>
+   * This provides full access to the API such as explicit transaction demarcation etc.
+   *
+   */
+  public EbeanServer db() {
+    return Ebean.getServer(serverName);
+  }
+
+  /**
+   * Return typically a different EbeanServer to the default.
+   * <p>
+   * This is equivalent to {@link Ebean#getServer(String)}
+   *
+   * @param server
+   *          The name of the EbeanServer. If this is null then the default EbeanServer is
+   *          returned.
+   */
+  public EbeanServer db(String server) {
+    return Ebean.getServer(server);
+  }
+
+  /**
+   * Creates an entity reference for this ID.
+   *
+   * <p>
+   * Equivalent to {@link EbeanServer#getReference(Class, Object)}
+   */
+  public T ref(I id) {
+    return db().getReference(type, id);
+  }
+
+  /**
+   * Retrieves an entity by ID.
+   *
+   * <p>
+   * Equivalent to {@link EbeanServer#find(Class, Object)}
+   */
+  @Nullable
+  public T byId(I id) {
+    return db().find(type, id);
+  }
+
+  /**
+   * Delete a bean by Id.
+   * <p>
+   * Equivalent to {@link EbeanServer#delete(Class, Object)}
+   */
+  public void deleteById(I id) {
+    db().delete(type, id);
+  }
+
+  /**
+   * Retrieves all entities of the given type.
+   */
+  public List<T> all() {
+    return query().findList();
+  }
+
+  /**
+   * Creates a query.
+   * <p>
+   * Equivalent to {@link EbeanServer#find(Class)}
+   */
+  public Query<T> query() {
+    return db().find(type);
+  }
+
+}

src/main/java/com/avaje/ebean/FutureList.java

@@ -2,7 +2,6 @@ package com.avaje.ebean;
 
 import javax.persistence.PersistenceException;
 import java.util.List;
-import java.util.concurrent.ExecutionException;
 import java.util.concurrent.Future;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.TimeoutException;

src/main/java/com/avaje/ebean/Model.java

@@ -441,6 +441,7 @@ public abstract class Model {
      *
      * }</pre>
      */
+    @SuppressWarnings("unchecked")
     public Find() {
       this.serverName = null;
       this.type = (Class<T>)ClassUtil.getSecondArgumentType(getClass());

src/main/java/com/avaje/ebean/PagedList.java

@@ -159,6 +159,11 @@ public interface PagedList<T> {
    */
   int getPageIndex();
 
+  /**
+   * Return the page size used for this query.
+   */
+  int getPageSize();
+
   /**
    * Return true if there is a next page.
    * <p>

src/main/java/com/avaje/ebean/Query.java

@@ -4,6 +4,7 @@ import com.avaje.ebean.text.PathProperties;
 import org.jetbrains.annotations.Nullable;
 
 import java.io.Serializable;
+import java.sql.Timestamp;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
@@ -285,6 +286,17 @@ public interface Query<T> extends Serializable {
    */
   Query<T> setRawSql(RawSql rawSql);
 
+  /**
+   * Perform an 'As of' query using history tables to return the object graph
+   * as of a time in the past.
+   * <p>
+   *   To perform this query the DB must have underlying history tables.
+   * </p>
+   *
+   * @param asOf the date time in the past at which you want to view the data
+   */
+  Query<T> asOf(Timestamp asOf);
+
   /**
    * Cancel the query execution if supported by the underlying database and
    * driver.
@@ -708,6 +720,41 @@ public interface Query<T> extends Serializable {
   @Nullable
   T findUnique();
 
+  /**
+   * Return versions of a @History entity bean.
+   * <p>
+   *   Note that this query will work against view based history implementations
+   *   but not sql2011 standards based implementations that require a start and
+   *   end timestamp to be specified.
+   * </p>
+   * <p>
+   *   Generally this query is expected to be a find by id or unique predicates query.
+   *   It will execute the query against the history returning the versions of the bean.
+   * </p>
+   */
+  List<Version<T>> findVersions();
+
+  /**
+   * Return versions of a @History entity bean between the 2 timestamps.
+   * <p>
+   *   Generally this query is expected to be a find by id or unique predicates query.
+   *   It will execute the query against the history returning the versions of the bean.
+   * </p>
+   */
+  List<Version<T>> findVersionsBetween(Timestamp start, Timestamp end);
+
+  /**
+   * Execute as a delete query deleting the 'root level' beans that match the predicates
+   * in the query.
+   * <p>
+   * Note that if the query includes joins then the generated delete statement may not be
+   * optimal depending on the database platform.
+   * </p>
+   *
+   * @return the number of beans/rows that were deleted.
+   */
+  int delete();
+
   /**
    * Return the count of entities this query should return.
    * <p>
@@ -1108,6 +1155,19 @@ public interface Query<T> extends Serializable {
 
   /**
    * Set whether this query uses DISTINCT.
+   * <p>
+   * The select() clause MUST be specified when setDistinct(true) is set. The reason for this is that
+   * generally ORM queries include the "id" property and this doesn't make sense for distinct queries.
+   * </p>
+   * <pre>{@code
+   *
+   *   List<Customer> customers =
+   *       Ebean.find(Customer.class)
+   *          .setDistinct(true)
+   *          .select("name")
+   *          .findList();
+   *
+   * }</pre>
    */
   Query<T> setDistinct(boolean isDistinct);
 
@@ -1236,4 +1296,11 @@ public interface Query<T> extends Serializable {
    */
   Class<T> getBeanType();
 
+  /**
+   * Set true if you want to disable lazy loading.
+   * <p>
+   *   That is, once the object graph is returned further lazy loading is disabled.
+   * </p>
+   */
+  Query<T> setDisableLazyLoading(boolean disableLazyLoading);
 }

src/main/java/com/avaje/ebean/SqlRow.java

@@ -153,7 +153,7 @@ public interface SqlRow extends Serializable, Map<String, Object> {
   /**
    * Put all the values from t into this map.
    */
-  void putAll(Map<? extends String, ? extends Object> t);
+  void putAll(Map<? extends String, ?> t);
 
   /**
    * Return the size of the map.

src/main/java/com/avaje/ebean/Transaction.java

@@ -2,7 +2,6 @@ package com.avaje.ebean;
 
 import com.avaje.ebean.config.PersistBatch;
 
-import javax.persistence.OptimisticLockException;
 import javax.persistence.PersistenceException;
 import javax.persistence.RollbackException;
 import java.io.Closeable;
@@ -97,6 +96,17 @@ public interface Transaction extends Closeable {
    */
   void setPersistCascade(boolean persistCascade);
 
+  /**
+   * Set to true when you want all loaded properties to be included in the update
+   * (rather than just the changed properties).
+   * <p>
+   *   You might set this when using JDBC batch in order to get multiple updates
+   *   with slightly different sets of changed properties into the same statement
+   *   and hence better JDBC batch performance.
+   * </p>
+   */
+  void setUpdateAllLoadedProperties(boolean updateAllLoadedProperties);
+
   /**
    * Turn on or off statement batching. Statement batching can be transparent
    * for drivers and databases that support getGeneratedKeys. Otherwise you may
@@ -279,7 +289,7 @@ public interface Transaction extends Closeable {
    * <li>Transaction commit occurs</li>
    * </ul>
    */
-  void flushBatch() throws PersistenceException, OptimisticLockException;
+  void flushBatch() throws PersistenceException;
 
   /**
    * Return the underlying Connection object.

src/main/java/com/avaje/ebean/TxType.java

@@ -46,5 +46,5 @@ public enum TxType {
    * If there is an existing transaction throws an Exception. Method runs
    * without a transaction.
    */
-  NEVER;
+  NEVER
 }

src/main/java/com/avaje/ebean/ValuePair.java

@@ -5,10 +5,19 @@ package com.avaje.ebean;
  */
 public class ValuePair {
 
-  private final Object newValue;
+  protected Object newValue;
 
-  private final Object oldValue;
+  protected Object oldValue;
 
+  /**
+   * Default constructor for JSON tools.
+   */
+  public ValuePair() {
+  }
+
+  /**
+   * Construct with the pair of new and old values.
+   */
   public ValuePair(Object newValue, Object oldValue) {
     this.newValue = newValue;
     this.oldValue = oldValue;
@@ -27,21 +36,19 @@ public class ValuePair {
   public Object getOldValue() {
     return oldValue;
   }
-  
+
   /**
-   * Return the new value.
+   * Set the new value.
    */
-  @Deprecated
-  public Object getValue1() {
-    return newValue;
+  public void setNewValue(Object newValue) {
+    this.newValue = newValue;
   }
 
   /**
-   * Return the old value.
+   * Set the old value.
    */
-  @Deprecated
-  public Object getValue2() {
-    return oldValue;
+  public void setOldValue(Object oldValue) {
+    this.oldValue = oldValue;
   }
 
   public String toString() {

src/main/java/com/avaje/ebean/Version.java

@@ -0,0 +1,101 @@
+package com.avaje.ebean;
+
+import java.sql.Timestamp;
+import java.util.Map;
+
+/**
+ * Wraps a version of a @History bean.
+ */
+public class Version<T> {
+
+  /**
+   * The version of the bean.
+   */
+  protected T bean;
+
+  /**
+   * The effective start date time of this version.
+   */
+  protected Timestamp start;
+
+  /**
+   * The effective end date time of this version.
+   */
+  protected Timestamp end;
+
+  /**
+   * The map of changed properties.
+   */
+  protected Map<String, ValuePair> diff;
+
+  /**
+   * Construct with bean and an effective date time range.
+   */
+  public Version(T bean, Timestamp start, Timestamp end) {
+    this.bean = bean;
+    this.start = start;
+    this.end = end;
+  }
+
+  /**
+   * Default constructor - useful for JSON tools such as Jackson.
+   */
+  public Version() {
+  }
+
+  /**
+   * Return the bean instance for this version.
+   */
+  public T getBean() {
+    return bean;
+  }
+
+  /**
+   * Set the bean instance for this version.
+   */
+  public void setBean(T bean) {
+    this.bean = bean;
+  }
+
+  /**
+   * Return the effective start date time of this version.
+   */
+  public Timestamp getStart() {
+    return start;
+  }
+
+  /**
+   * Set the effective start date time of this version.
+   */
+  public void setStart(Timestamp start) {
+    this.start = start;
+  }
+
+  /**
+   * Return the effective end date time of this version.
+   */
+  public Timestamp getEnd() {
+    return end;
+  }
+
+  /**
+   * Set the effective end date time of this version.
+   */
+  public void setEnd(Timestamp end) {
+    this.end = end;
+  }
+
+  /**
+   * Set the map of differences from this bean to the prior version.
+   */
+  public void setDiff(Map<String, ValuePair> diff) {
+    this.diff = diff;
+  }
+
+  /**
+   * Return the map of differences from this bean to the prior version.
+   */
+  public Map<String, ValuePair> getDiff() {
+    return diff;
+  }
+}

src/main/java/com/avaje/ebean/annotation/ChangeLog.java

@@ -0,0 +1,34 @@
+package com.avaje.ebean.annotation;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+/**
+ * Marks an entity bean as being included in the change logging.
+ */
+@Target({ElementType.TYPE})
+@Retention(RetentionPolicy.RUNTIME)
+public @interface ChangeLog {
+
+  /**
+   * Specify if inserts should be explicitly Included or Excluded.
+   * <p>
+   * If not defined explicitly then the server default behaviour defined
+   * on ServerConfig is used.
+   * </p>
+   */
+  ChangeLogInsertMode inserts() default ChangeLogInsertMode.DEFAULT;
+
+  /**
+   * When specified only include update requests that have at least one
+   * of the given properties as a dirty property.
+   * <p>
+   * This provides a way to filter requests to include in the change log such that
+   * only updates that include at least one of the given properties is included
+   * in the change log.
+   * </p>
+   */
+  String[] updatesThatInclude() default {};
+}

src/main/java/com/avaje/ebean/annotation/ChangeLogInsertMode.java

@@ -0,0 +1,22 @@
+package com.avaje.ebean.annotation;
+
+/**
+ * The mode used to determine if inserts should be included or not for a given bean type.
+ */
+public enum ChangeLogInsertMode {
+
+  /**
+   * Use the default behaviour as defined on ServerConfig.
+   */
+  DEFAULT,
+
+  /**
+   * Include inserts in the change log.
+   */
+  INCLUDE,
+
+  /**
+   * Exclude inserts in the change log.
+   */
+  EXCLUDE
+}

src/main/java/com/avaje/ebean/annotation/History.java

@@ -0,0 +1,19 @@
+package com.avaje.ebean.annotation;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+/**
+ * Marks an entity bean as having history support.
+ * <p>
+ * In Postgres for example this means there is an associated history table which is
+ * typically automatically populated via database triggers.
+ * </p>
+ */
+@Target({ ElementType.TYPE })
+@Retention(RetentionPolicy.RUNTIME)
+public @interface History {
+
+}

src/main/java/com/avaje/ebean/annotation/HistoryExclude.java

@@ -0,0 +1,25 @@
+package com.avaje.ebean.annotation;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+/**
+ * Marks a property as being excluded from history.
+ * <p>
+ * This means the property values are not maintained in the history table. Typically this
+ * would be placed on relatively large properties (Clobs, Blobs, large varchar columns etc)
+ * that are considered not interesting enough to maintain history on excluding them reduces
+ * underlying database costs.
+ * </p>
+ * <p>
+ * When placed on a ManyToMany this means that the intersection table does not have history
+ * support.
+ * </p>
+ */
+@Target({ ElementType.FIELD })
+@Retention(RetentionPolicy.RUNTIME)
+public @interface HistoryExclude {
+
+}

src/main/java/com/avaje/ebean/annotation/Index.java

@@ -10,15 +10,24 @@ import java.lang.annotation.Target;
  *
  * @author rvbiljouw
  */
-@Target({ElementType.FIELD})
+@Target({ElementType.TYPE, ElementType.FIELD})
 @Retention(RetentionPolicy.RUNTIME)
 public @interface Index {
 
   /**
-   * Name of the index
-   *
-   * @return index name
+   * Name of the index. If left blank a name is derived using the built in naming convention.
    */
-  String value() default "";
+  String name() default "";
+
+  /**
+   * If set true indicates this is a unique index.
+   */
+  boolean unique() default false;
+
+  /**
+   * When placed on the class (rather than field) you can specify the columns
+   * to include in the index in order.
+   */
+  String[] columnNames() default {};
 
 }

src/main/java/com/avaje/ebean/annotation/WhenCreated.java

@@ -0,0 +1,38 @@
+package com.avaje.ebean.annotation;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+/**
+ * For a timestamp property that is set to the datetime when the entity is
+ * created/inserted.
+ * <p>
+ * This is effectively an alias for @CreatedTimestamp and added to hint
+ * towards a better naming convention (WhenCreated, WhenModified).
+ * </p>
+ * <p>
+ * An alternative to using this annotation would be to use insertable=false,
+ * updateable=false with @Column and have the DB insert the current time
+ * (default value on the DB column is SYSTIME etc).
+ * </p>
+ * <p>
+ * The downside to this approach is that the inserted entity does not have the
+ * timestamp value after the insert has occurred. You need to fetch the entity
+ * back to get the inserted timestamp if you want to used it.
+ * </p>
+ *
+ * <h3>Example:</h3>
+ * <pre>{@code
+ *
+ *   @WhenCreated
+ *   Timestamp whenCreated;
+ *
+ * }</pre>
+ */
+@Target({ ElementType.FIELD, ElementType.METHOD })
+@Retention(RetentionPolicy.RUNTIME)
+public @interface WhenCreated {
+
+}

src/main/java/com/avaje/ebean/annotation/WhenModified.java

@@ -0,0 +1,20 @@
+package com.avaje.ebean.annotation;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+/**
+ * For a timestamp property that is set to the datetime when the entity was last modified.
+ * <p>
+ * This is effectively an alias for @UpdatedTimestamp and added to hint
+ * towards a better naming convention (WhenCreated, WhenModified).
+ * </p>
+ * </p>
+ */
+@Target({ ElementType.FIELD, ElementType.METHOD })
+@Retention(RetentionPolicy.RUNTIME)
+public @interface WhenModified {
+
+}

src/main/java/com/avaje/ebean/annotation/WhoCreated.java

@@ -0,0 +1,29 @@
+package com.avaje.ebean.annotation;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+/**
+ * Mapped onto a entity bean property that represents the user id of
+ * who created the entity>
+ * <p>
+ * To use this annotation you need to implement CurrentUserProvider.
+ * The type of the bean property should match the type returned by
+ * CurrentUserProvider.
+ *</p>
+
+ * <h3>Example:</h3>
+ * <pre>{@code
+ *
+ *   @WhoCreated
+ *   String whoCreated;
+ *
+ * }</pre>
+ */
+@Target({ ElementType.FIELD, ElementType.METHOD })
+@Retention(RetentionPolicy.RUNTIME)
+public @interface WhoCreated {
+
+}

src/main/java/com/avaje/ebean/annotation/WhoModified.java

@@ -0,0 +1,29 @@
+package com.avaje.ebean.annotation;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+/**
+ * Mapped onto a entity bean property that represents the user id of
+ * who last modified the entity>
+ * <p>
+ * To use this annotation you need to implement CurrentUserProvider.
+ * The type of the bean property should match the type returned by
+ * CurrentUserProvider.
+ * </p>
+ *
+ * <h3>Example:</h3>
+ * <pre>{@code
+ *
+ *   @WhoModified
+ *   String whoModified;
+ *
+ * }</pre>
+ */
+@Target({ElementType.FIELD, ElementType.METHOD})
+@Retention(RetentionPolicy.RUNTIME)
+public @interface WhoModified {
+
+}

src/main/java/com/avaje/ebean/bean/EntityBeanIntercept.java

@@ -45,7 +45,7 @@ public final class EntityBeanIntercept implements Serializable {
   /**
    * The actual entity bean that 'owns' this intercept.
    */
-  private EntityBean owner;
+  private final EntityBean owner;
 
   private EntityBean embeddedOwner;
   private int embeddedOwnerIndex;
@@ -72,7 +72,7 @@ public final class EntityBeanIntercept implements Serializable {
   /**
    * Used when a bean is partially filled.
    */
-  private boolean[] loadedProps;
+  private final boolean[] loadedProps;
   
   private boolean fullyLoadedBean;
 
@@ -581,7 +581,29 @@ public final class EntityBeanIntercept implements Serializable {
       }
     }
   }
-  
+
+  /**
+   * Return true if any of the given property names are dirty.
+   */
+  public boolean hasDirtyProperty(Set<String> propertyNames) {
+
+    String[] names = owner._ebean_getPropertyNames();
+    int len = getPropertyLength();
+    for (int i = 0; i < len; i++) {
+      if (changedProps != null && changedProps[i]) {
+        // the property has been changed on this bean
+        if (propertyNames.contains(names[i])) {
+          return true;
+        }
+      } else if (embeddedDirty != null && embeddedDirty[i]) {
+        if (propertyNames.contains(names[i])) {
+          return true;
+        }
+      }
+    }
+    return false;
+  }
+
   /**
    * Return a map of dirty properties with their new and old values.
    */
@@ -608,7 +630,7 @@ public final class EntityBeanIntercept implements Serializable {
       } else if (embeddedDirty != null && embeddedDirty[i]) {
         // an embedded property has been changed - recurse
         EntityBean embeddedBean = (EntityBean)owner._ebean_getField(i);
-        embeddedBean._ebean_getIntercept().addDirtyPropertyValues(dirtyValues, getProperty(i)+".");
+        embeddedBean._ebean_getIntercept().addDirtyPropertyValues(dirtyValues, getProperty(i) + ".");
       }
     }
   }
@@ -638,6 +660,20 @@ public final class EntityBeanIntercept implements Serializable {
     return hash;
   }
 
+  /**
+   * Return a loaded property hash.
+   */
+  public int getLoadedPropertyHash() {
+    int hash = 37;
+    int len = getPropertyLength();
+    for (int i = 0; i < len; i++) {
+      if (isLoadedProperty(i)) {
+        hash = hash * 31 + (i+1);
+      }
+    }
+    return hash;
+  }
+
   /**
    * Return the set of property names for changed properties.
    */
@@ -877,7 +913,7 @@ public final class EntityBeanIntercept implements Serializable {
     } else {
       return null;
     }
-    return (pcs == null) ? null : new PropertyChangeEvent(owner, getProperty(propertyIndex), Boolean.valueOf(oldValue), Boolean.valueOf(newValue));
+    return (pcs == null) ? null : new PropertyChangeEvent(owner, getProperty(propertyIndex), oldValue, newValue);
   }
 
   /**
@@ -892,7 +928,7 @@ public final class EntityBeanIntercept implements Serializable {
     } else {
       return null;
     }
-    return (pcs == null) ? null : new PropertyChangeEvent(owner, getProperty(propertyIndex), Integer.valueOf(oldValue), Integer.valueOf(newValue));
+    return (pcs == null) ? null : new PropertyChangeEvent(owner, getProperty(propertyIndex), oldValue, newValue);
   }
 
   /**
@@ -908,7 +944,7 @@ public final class EntityBeanIntercept implements Serializable {
       return null;
     }
     
-    return (pcs == null) ? null : new PropertyChangeEvent(owner, getProperty(propertyIndex), Long.valueOf(oldValue), Long.valueOf(newValue));
+    return (pcs == null) ? null : new PropertyChangeEvent(owner, getProperty(propertyIndex), oldValue, newValue);
   }
 
   /**
@@ -923,7 +959,7 @@ public final class EntityBeanIntercept implements Serializable {
     } else {
       return null;
     }
-    return (pcs == null) ? null : new PropertyChangeEvent(owner, getProperty(propertyIndex), Double.valueOf(oldValue), Double.valueOf(newValue));
+    return (pcs == null) ? null : new PropertyChangeEvent(owner, getProperty(propertyIndex), oldValue, newValue);
   }
 
   /**
@@ -938,7 +974,7 @@ public final class EntityBeanIntercept implements Serializable {
     } else {
       return null;
     }
-    return (pcs == null) ? null :  new PropertyChangeEvent(owner, getProperty(propertyIndex), Float.valueOf(oldValue), Float.valueOf(newValue));
+    return (pcs == null) ? null :  new PropertyChangeEvent(owner, getProperty(propertyIndex), oldValue, newValue);
   }
 
   /**
@@ -953,7 +989,7 @@ public final class EntityBeanIntercept implements Serializable {
     } else {
       return null;
     }
-    return (pcs == null) ? null : new PropertyChangeEvent(owner, getProperty(propertyIndex), Short.valueOf(oldValue), Short.valueOf(newValue));
+    return (pcs == null) ? null : new PropertyChangeEvent(owner, getProperty(propertyIndex), oldValue, newValue);
   }
 
   /**
@@ -968,7 +1004,7 @@ public final class EntityBeanIntercept implements Serializable {
     } else {
       return null;
     }
-    return (pcs == null) ? null : new PropertyChangeEvent(owner, getProperty(propertyIndex), Character.valueOf(oldValue), Character.valueOf(newValue));
+    return (pcs == null) ? null : new PropertyChangeEvent(owner, getProperty(propertyIndex), oldValue, newValue);
   }
 
   /**
@@ -983,7 +1019,7 @@ public final class EntityBeanIntercept implements Serializable {
     } else {
       return null;
     }
-    return (pcs == null) ? null : new PropertyChangeEvent(owner, getProperty(propertyIndex), Byte.valueOf(oldValue), Byte.valueOf(newValue));
+    return (pcs == null) ? null : new PropertyChangeEvent(owner, getProperty(propertyIndex), oldValue, newValue);
   }
 
   /**

src/main/java/com/avaje/ebean/bean/ObjectGraphNode.java

@@ -82,6 +82,7 @@ public final class ObjectGraphNode implements Serializable {
     }
     
     ObjectGraphNode e = (ObjectGraphNode) obj;
+    //noinspection StringEquality
     return  ((e.path == path) || (e.path != null && e.path.equals(path)))
         && e.originQueryPoint.equals(originQueryPoint);
   }

src/main/java/com/avaje/ebean/bean/PersistenceContext.java

@@ -74,12 +74,12 @@ public interface PersistenceContext {
      * The bean was previously deleted from this persistence context (can't hit
      * L2 cache).
      */
-    public static WithOption DELETED = new WithOption(true);
+    public static final WithOption DELETED = new WithOption();
 
     private final boolean deleted;
     private final Object bean;
 
-    private WithOption(boolean deleted) {
+    private WithOption() {
       this.deleted = true;
       this.bean = null;
     }

src/main/java/com/avaje/ebean/cache/ServerCacheStatistics.java

@@ -40,7 +40,8 @@ public class ServerCacheStatistics {
   protected long evictByLRU;
 
   public String toString() {
-    StringBuilder sb = new StringBuilder();
+    //noinspection StringBufferReplaceableByString
+    StringBuilder sb = new StringBuilder(80);
     sb.append(cacheName);
     sb.append(" maxSize:").append(maxSize);
     sb.append(" size:").append(size);

src/main/java/com/avaje/ebean/common/BeanList.java

@@ -343,41 +343,41 @@ public final class BeanList<E> extends AbstractBeanCollection<E> implements List
     return list.remove(o);
   }
 
-  public boolean removeAll(Collection<?> c) {
+  public boolean removeAll(Collection<?> beans) {
     checkReadOnly();
     init();
     if (modifyRemoveListening) {
       boolean changed = false;
-      Iterator<?> it = c.iterator();
-      while (it.hasNext()) {
-        Object o = it.next();
-        if (list.remove(o)) {
-          modifyRemoval(o);
+      for (Object bean : beans) {
+        if (list.remove(bean)) {
+          // register this bean as having been removed
+          modifyRemoval(bean);
           changed = true;
         }
       }
       return changed;
     }
-    return list.removeAll(c);
+    return list.removeAll(beans);
   }
 
-  public boolean retainAll(Collection<?> c) {
+  public boolean retainAll(Collection<?> retainBeans) {
     checkReadOnly();
     init();
     if (modifyRemoveListening) {
       boolean changed = false;
       Iterator<E> it = list.iterator();
       while (it.hasNext()) {
-        Object o = it.next();
-        if (!c.contains(o)) {
+        Object bean = it.next();
+        if (!retainBeans.contains(bean)) {
+          // removing this bean
           it.remove();
-          modifyRemoval(o);
+          modifyRemoval(bean);
           changed = true;
         }
       }
       return changed;
     }
-    return list.retainAll(c);
+    return list.retainAll(retainBeans);
   }
 
   public E set(int index, E element) {
@@ -415,6 +415,7 @@ public final class BeanList<E> extends AbstractBeanCollection<E> implements List
 
   public <T> T[] toArray(T[] a) {
     init();
+    //noinspection SuspiciousToArrayCall
     return list.toArray(a);
   }
 

src/main/java/com/avaje/ebean/common/BeanMap.java

@@ -1,15 +1,14 @@
 package com.avaje.ebean.common;
 
-import java.util.Collection;
-import java.util.Collections;
-import java.util.Iterator;
-import java.util.LinkedHashMap;
-import java.util.Map;
-import java.util.Set;
-
 import com.avaje.ebean.bean.BeanCollectionLoader;
 import com.avaje.ebean.bean.EntityBean;
 
+import java.util.Collection;
+import java.util.Collections;
+import java.util.LinkedHashMap;
+import java.util.Map;
+import java.util.Set;
+
 /**
  * Map capable of lazy loading.
  */
@@ -148,8 +147,7 @@ public final class BeanMap<K, E> extends AbstractBeanCollection<E> implements Ma
   public Collection<E> getActualDetails() {
     return map.values();
   }
-  
-  
+
   /**
    * Returns the map entrySet.
    * <p>
@@ -159,7 +157,6 @@ public final class BeanMap<K, E> extends AbstractBeanCollection<E> implements Ma
    */
   public Collection<?> getActualEntries() {
     return map.entrySet();
-
   }
 
   public String toString() {
@@ -195,9 +192,9 @@ public final class BeanMap<K, E> extends AbstractBeanCollection<E> implements Ma
     checkReadOnly();
     initClear();
     if (modifyRemoveListening) {
-      for (K key : map.keySet()) {
-        E o = map.remove(key);
-        modifyRemoval(o);
+      // add all beans to the removal list
+      for (E bean : map.values()) {
+        modifyRemoval(bean);
       }
     }
     map.clear();
@@ -249,27 +246,30 @@ public final class BeanMap<K, E> extends AbstractBeanCollection<E> implements Ma
     checkReadOnly();
     init();
     if (modifyListening) {
-      Object o = map.put(key, value);
-      modifyAddition(value);
-      modifyRemoval(o);
+      Object oldBean = map.put(key, value);
+      if (value != oldBean) {
+        // register the add of the new and the removal of the old
+        modifyAddition(value);
+        modifyRemoval(oldBean);
+      }
     }
     return map.put(key, value);
   }
 
   @SuppressWarnings({ "unchecked", "rawtypes" })
-  public void putAll(Map<? extends K, ? extends E> t) {
+  public void putAll(Map<? extends K, ? extends E> puts) {
     checkReadOnly();
     init();
     if (modifyListening) {
-      Iterator it = t.entrySet().iterator();
-      while (it.hasNext()) {
-        Map.Entry entry = (Map.Entry) it.next();
-        Object o = map.put((K) entry.getKey(), (E) entry.getValue());
-        modifyAddition((E) entry.getValue());
-        modifyRemoval(o);
+      for (Entry<? extends K, ? extends E> entry : puts.entrySet()) {
+        Object oldBean = map.put(entry.getKey(), entry.getValue());
+        if (entry.getValue() != oldBean) {
+          modifyAddition(entry.getValue());
+          modifyRemoval(oldBean);
+        }
       }
     }
-    map.putAll(t);
+    map.putAll(puts);
   }
 
   public E remove(Object key) {

src/main/java/com/avaje/ebean/common/BeanSet.java

@@ -192,32 +192,29 @@ public final class BeanSet<E> extends AbstractBeanCollection<E> implements Set<E
     return set.add(o);
   }
 
-  public boolean addAll(Collection<? extends E> c) {
+  public boolean addAll(Collection<? extends E> addCollection) {
     checkReadOnly();
     init();
     if (modifyAddListening) {
       boolean changed = false;
-      Iterator<? extends E> it = c.iterator();
-      while (it.hasNext()) {
-        E o = it.next();
-        if (set.add(o)) {
-          modifyAddition(o);
+      for (E bean : addCollection) {
+        if (set.add(bean)) {
+          // register the addition of the bean
+          modifyAddition(bean);
           changed = true;
         }
       }
       return changed;
     }
-    return set.addAll(c);
+    return set.addAll(addCollection);
   }
 
   public void clear() {
     checkReadOnly();
     initClear();
     if (modifyRemoveListening) {
-      Iterator<E> it = set.iterator();
-      while (it.hasNext()) {
-        E e = it.next();
-        modifyRemoval(e);
+      for (E bean : set) {
+        modifyRemoval(bean);
       }
     }
     set.clear();
@@ -262,41 +259,40 @@ public final class BeanSet<E> extends AbstractBeanCollection<E> implements Set<E
     return set.remove(o);
   }
 
-  public boolean removeAll(Collection<?> c) {
+  public boolean removeAll(Collection<?> beans) {
     checkReadOnly();
     init();
     if (modifyRemoveListening) {
       boolean changed = false;
-      Iterator<?> it = c.iterator();
-      while (it.hasNext()) {
-        Object o = it.next();
-        if (set.remove(o)) {
-          modifyRemoval(o);
+      for (Object bean : beans) {
+        if (set.remove(bean)) {
+          modifyRemoval(bean);
           changed = true;
         }
       }
       return changed;
     }
-    return set.removeAll(c);
+    return set.removeAll(beans);
   }
 
-  public boolean retainAll(Collection<?> c) {
+  public boolean retainAll(Collection<?> beans) {
     checkReadOnly();
     init();
     if (modifyRemoveListening) {
       boolean changed = false;
       Iterator<?> it = set.iterator();
       while (it.hasNext()) {
-        Object o = it.next();
-        if (!c.contains(o)) {
+        Object bean = it.next();
+        if (!beans.contains(bean)) {
+          // not retaining this bean so add it to the removal list
           it.remove();
-          modifyRemoval(o);
+          modifyRemoval(bean);
           changed = true;
         }
       }
       return changed;
     }
-    return set.retainAll(c);
+    return set.retainAll(beans);
   }
 
   public int size() {
@@ -311,6 +307,7 @@ public final class BeanSet<E> extends AbstractBeanCollection<E> implements Set<E
 
   public <T> T[] toArray(T[] a) {
     init();
+    //noinspection SuspiciousToArrayCall
     return set.toArray(a);
   }
 

src/main/java/com/avaje/ebean/common/ModifyCollection.java

@@ -40,9 +40,7 @@ class ModifyCollection<E> implements Collection<E> {
 
   public boolean addAll(Collection<? extends E> collection) {
     boolean changed = false;
-    Iterator<? extends E> it = collection.iterator();
-    while (it.hasNext()) {
-      E o = it.next();
+    for (E o : collection) {
       if (c.add(o)) {
         owner.modifyAddition(o);
         changed = true;
@@ -51,27 +49,33 @@ class ModifyCollection<E> implements Collection<E> {
     return changed;
   }
 
+  @Override
   public void clear() {
     c.clear();
   }
 
+  @Override
   public boolean contains(Object o) {
     return c.contains(o);
   }
 
+  @Override
   public boolean containsAll(Collection<?> collection) {
     return c.containsAll(collection);
   }
 
+  @Override
   public boolean isEmpty() {
     return c.isEmpty();
   }
 
+  @Override
   public Iterator<E> iterator() {
     Iterator<E> it = c.iterator();
     return new ModifyIterator<E>(owner, it);
   }
 
+  @Override
   public boolean remove(Object o) {
     if (c.remove(o)) {
       owner.modifyRemoval(o);
@@ -80,42 +84,47 @@ class ModifyCollection<E> implements Collection<E> {
     return false;
   }
 
+  @Override
   public boolean removeAll(Collection<?> collection) {
     boolean changed = false;
-    Iterator<?> it = collection.iterator();
-    while (it.hasNext()) {
-      Object o = (Object) it.next();
-      if (c.remove(o)) {
-        owner.modifyRemoval(o);
+    for (Object bean : collection) {
+      if (c.remove(bean)) {
+        owner.modifyRemoval(bean);
         changed = true;
       }
     }
     return changed;
   }
 
+  @Override
   public boolean retainAll(Collection<?> collection) {
     boolean changed = false;
     Iterator<?> it = c.iterator();
     while (it.hasNext()) {
-      Object o = (Object) it.next();
-      if (!collection.contains(o)) {
+      Object bean = it.next();
+      if (!collection.contains(bean)) {
+        // not retaining this bean so add to removals
         it.remove();
-        owner.modifyRemoval(o);
+        owner.modifyRemoval(bean);
         changed = true;
       }
     }
     return changed;
   }
 
+  @Override
   public int size() {
     return c.size();
   }
 
+  @Override
   public Object[] toArray() {
     return c.toArray();
   }
 
+  @Override
   public <T> T[] toArray(T[] a) {
+    //noinspection SuspiciousToArrayCall
     return c.toArray(a);
   }
 

src/main/java/com/avaje/ebean/common/ModifyHolder.java

@@ -58,7 +58,7 @@ class ModifyHolder<E> implements Serializable {
   void modifyRemoval(Object bean) {
     if (bean != null) {
       // If it is to be added then just remove the addition
-      if (!modifyAdditions.remove((E) bean)) {
+      if (!modifyAdditions.remove(bean)) {
         modifyDeletions.add((E) bean);
       }
     }

src/main/java/com/avaje/ebean/common/ModifyList.java

@@ -1,7 +1,6 @@
 package com.avaje.ebean.common;
 
 import java.util.Collection;
-import java.util.Iterator;
 import java.util.List;
 import java.util.ListIterator;
 
@@ -39,12 +38,10 @@ class ModifyList<E> extends ModifyCollection<E> implements List<E> {
     owner.modifyAddition(element);
   }
 
-  public boolean addAll(int index, Collection<? extends E> co) {
-    if (list.addAll(index, co)) {
-      Iterator<? extends E> it = co.iterator();
-      while (it.hasNext()) {
-        E o = it.next();
-        owner.modifyAddition(o);
+  public boolean addAll(int index, Collection<? extends E> addCollection) {
+    if (list.addAll(index, addCollection)) {
+      for (E bean : addCollection) {
+        owner.modifyAddition(bean);
       }
       return true;
     }

src/main/java/com/avaje/ebean/common/ModifyListIterator.java

@@ -67,9 +67,7 @@ class ModifyListIterator<E> implements ListIterator<E> {
   }
 
   public void set(E o) {
-    if (last == null) {
-      // in theory this is not allowed
-    } else {
+    if (last != null) {
       owner.modifyRemoval(last);
       owner.modifyAddition(o);
     }

src/main/java/com/avaje/ebean/config/AbstractNamingConvention.java

@@ -1,12 +1,10 @@
 package com.avaje.ebean.config;
 
+import com.avaje.ebean.config.dbplatform.DatabasePlatform;
+
 import javax.persistence.Inheritance;
 import javax.persistence.Table;
 
-import com.avaje.ebean.config.dbplatform.DatabasePlatform;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
-
 /**
  * Provides some base implementation for NamingConventions.
  *
@@ -14,31 +12,39 @@ import org.slf4j.LoggerFactory;
  */
 public abstract class AbstractNamingConvention implements NamingConvention {
 
-  /** The Constant logger. */
-  private static final Logger logger = LoggerFactory.getLogger(AbstractNamingConvention.class);
-
-  /** The Constant DEFAULT_SEQ_FORMAT. */
+  /**
+   * The Constant DEFAULT_SEQ_FORMAT.
+   */
   public static final String DEFAULT_SEQ_FORMAT = "{table}_seq";
 
-  /** Sequence Format that includes the Primary Key column */
+  /**
+   * Sequence Format that includes the Primary Key column
+   */
   public static final String TABLE_PKCOLUMN_SEQ_FORMAT = "{table}_{column}_seq";
 
-  /** The catalog. */
+  /**
+   * The catalog.
+   */
   private String catalog;
 
-  /** The schema. */
+  /**
+   * The schema.
+   */
   private String schema;
 
-  /** The sequence format. */
+  /**
+   * The sequence format.
+   */
   private String sequenceFormat;
 
-  /** The database platform. */
+  /**
+   * The database platform.
+   */
   protected DatabasePlatform databasePlatform;
 
-  /** The max length of constraint names. */
-  protected int maxConstraintNameLength;
-
-  /** Used to trim off extra prefix for M2M. */
+  /**
+   * Used to trim off extra prefix for M2M.
+   */
   protected int rhsPrefixLength = 3;
 
   protected boolean useForeignKeyPrefix;
@@ -62,8 +68,7 @@ public abstract class AbstractNamingConvention implements NamingConvention {
   }
 
   /**
-   * Construct with the default sequence format ("{table}_seq") and
-   * useForeignKeyPrefix as true.
+   * Construct with the default sequence format ("{table}_seq") and useForeignKeyPrefix as true.
    */
   public AbstractNamingConvention() {
     this(DEFAULT_SEQ_FORMAT);
@@ -71,9 +76,6 @@ public abstract class AbstractNamingConvention implements NamingConvention {
 
   public void setDatabasePlatform(DatabasePlatform databasePlatform) {
     this.databasePlatform = databasePlatform;
-    this.maxConstraintNameLength = databasePlatform.getDbDdlSyntax().getMaxConstraintNameLength();
-
-    logger.trace("Using maxConstraintNameLength of " + maxConstraintNameLength);
   }
 
   public String getSequenceName(String tableName, String pkColumn) {
@@ -218,11 +220,11 @@ public abstract class AbstractNamingConvention implements NamingConvention {
     }
     buffer.append(rhsTableName);
 
-    int maxConstraintNameLength = databasePlatform.getDbDdlSyntax().getMaxConstraintNameLength();
+    int maxTableNameLength = databasePlatform.getMaxTableNameLength();
 
     // maxConstraintNameLength is used as the max table name length.
-    if (buffer.length() > maxConstraintNameLength) {
-      buffer.setLength(maxConstraintNameLength);
+    if (buffer.length() > maxTableNameLength) {
+      buffer.setLength(maxTableNameLength);
     }
 
     return new TableName(lhsTable.getCatalog(), lhsTable.getSchema(), buffer.toString());
@@ -239,7 +241,7 @@ public abstract class AbstractNamingConvention implements NamingConvention {
     if (t != null && !isEmpty(t.name())) {
       // Note: empty catalog and schema are converted to null
       // Only need to convert quoted identifiers from annotations
-      return new TableName(quoteIdentifiers(t.catalog()), quoteIdentifiers(t.schema()),  quoteIdentifiers(t.name()));
+      return new TableName(quoteIdentifiers(t.catalog()), quoteIdentifiers(t.schema()), quoteIdentifiers(t.name()));
     }
 
     // No annotation
@@ -272,10 +274,7 @@ public abstract class AbstractNamingConvention implements NamingConvention {
    * Checks string is null or empty .
    */
   protected boolean isEmpty(String s) {
-    if (s == null || s.trim().length() == 0) {
-      return true;
-    }
-    return false;
+    return s == null || s.trim().length() == 0;
   }
 
   /**

src/main/java/com/avaje/ebean/config/CurrentUserProvider.java

@@ -0,0 +1,16 @@
+package com.avaje.ebean.config;
+
+/**
+ * Provides the current user in order to support 'Who created', 'Who modified' and other audit features.
+ */
+public interface CurrentUserProvider {
+
+  /**
+   * Return the current user id.
+   * <p>
+   *   The type returned should match the type of the properties annotated
+   *   with @WhoCreated and @WhoModified. These are typically String, Long or UUID.
+   * </p>
+   */
+  Object currentUser();
+}

src/main/java/com/avaje/ebean/config/DataSourceConfig.java

@@ -507,8 +507,7 @@ public class DataSourceConfig {
 
     String customProperties = properties.get("customProperties", null);
     if (customProperties != null && customProperties.length() > 0) {
-      Map<String, String> custProps = StringHelper.delimitedToMap(customProperties, ";", "=");
-      this.customProperties = custProps;
+      this.customProperties = StringHelper.delimitedToMap(customProperties, ";", "=");
     }
 
   }

src/main/java/com/avaje/ebean/config/DbConstraintNaming.java

@@ -0,0 +1,192 @@
+package com.avaje.ebean.config;
+
+/**
+ * Naming convention used for constraint names.
+ * <p>
+ * Note that these constraint names are trimmed in the PlatformDdl which can be overridden
+ * but provides a decent default implementation.
+ * </p>
+ */
+public class DbConstraintNaming {
+
+  /**
+   * Defines how constraint names are shortened if required based on platform limitations.
+   */
+  public interface MaxLength {
+
+    /**
+     * Truncate or shorten the constraint name to support DB platform limitations.
+     * <p>
+     * There is a default implementation of this which is used if an implementation is
+     * not specified.
+     * </p>
+     */
+    String maxLength(String constraintName, int count);
+  }
+
+  protected String pkPrefix = "pk_";
+  protected String pkSuffix = "";
+
+  protected String fkPrefix = "fk_";
+  protected String fkMiddle = "_";
+  protected String fkSuffix = "";
+
+  protected String fkIndexPrefix = "ix_";
+  protected String fkIndexMiddle = "_";
+  protected String fkIndexSuffix = "";
+
+  protected String indexPrefix = "ix_";
+  protected String indexMiddle = "_";
+  protected String indexSuffix = "";
+
+  protected String uqPrefix = "uq_";
+  protected String uqSuffix = "";
+
+  protected String ckPrefix = "ck_";
+  protected String ckSuffix = "";
+
+  protected boolean lowerCaseNames = true;
+
+  protected MaxLength maxLength;
+
+  protected DbConstraintNormalise normalise = new DbConstraintNormalise();
+
+  public DbConstraintNaming() {
+  }
+
+  /**
+   * Return the MaxLength implementation used to truncate/shorten db constraint names as necessary.
+   */
+  public MaxLength getMaxLength() {
+    return maxLength;
+  }
+
+  /**
+   * Set the MaxLength implementation used to truncate/shorten db constraint names as necessary.
+   */
+  public void setMaxLength(MaxLength maxLength) {
+    this.maxLength = maxLength;
+  }
+
+  /**
+   * Return the primary key constraint name.
+   */
+  public String primaryKeyName(String tableName) {
+
+    return pkPrefix + normaliseTable(tableName) + pkSuffix;
+  }
+
+  /**
+   * Return the foreign key constraint name given a single column foreign key.
+   */
+  public String foreignKeyConstraintName(String tableName, String columnName) {
+    return fkPrefix + normaliseTable(tableName) + fkMiddle + normaliseColumn(columnName) + fkSuffix;
+  }
+
+  /**
+   * Return the index name associated with a foreign key constraint given multiple columns.
+   */
+  public String foreignKeyIndexName(String tableName, String[] columns) {
+
+    String colPart = joinColumnNames(columns);
+    return fkIndexPrefix + normaliseTable(tableName) + fkIndexMiddle + colPart + fkIndexSuffix;
+  }
+
+  /**
+   * Return the index name associated with a foreign key constraint given a single column foreign key.
+   */
+  public String foreignKeyIndexName(String tableName, String column) {
+
+    String colPart = normaliseTable(column);
+    return fkIndexPrefix + normaliseTable(tableName) + fkIndexMiddle + colPart + fkIndexSuffix;
+  }
+
+  /**
+   * Return the index name for a general index (not associated with a foreign key).
+   */
+  public String indexName(String tableName, String column) {
+
+    String colPart = normaliseTable(column);
+    return indexPrefix + normaliseTable(tableName) + indexMiddle + colPart + indexSuffix;
+  }
+
+  /**
+   * Return the index name for a general index (not associated with a foreign key).
+   */
+  public String indexName(String tableName, String[] columns) {
+
+    String colPart = joinColumnNames(columns);
+    return indexPrefix + normaliseTable(tableName) + indexMiddle + colPart + indexSuffix;
+  }
+
+  /**
+   * Join the column names together with underscores.
+   */
+  protected String joinColumnNames(String[] columns) {
+
+    if (columns.length == 1) {
+      return normaliseColumn(columns[0]);
+    }
+    StringBuilder sb = new StringBuilder();
+    for (int i = 0; i < columns.length; i++) {
+      if (i > 0) {
+        sb.append("_");
+      }
+      sb.append(normaliseColumn(columns[i]));
+    }
+    return sb.toString();
+  }
+
+  /**
+   * Return the unique constraint name.
+   */
+  public String uniqueConstraintName(String tableName, String columnName) {
+
+    return uqPrefix + normaliseTable(tableName) + "_" + normaliseColumn(columnName) + uqSuffix;
+  }
+
+  /**
+   * Return the unique constraint name.
+   */
+  public String uniqueConstraintName(String tableName, String[] columns) {
+
+    String colPart = joinColumnNames(columns);
+    return uqPrefix + normaliseTable(tableName) + "_" + colPart + uqSuffix;
+  }
+
+  /**
+   * Return the check constraint name.
+   */
+  public String checkConstraintName(String tableName, String columnName) {
+
+    return ckPrefix + normaliseTable(tableName) + "_" + normaliseColumn(columnName) + ckSuffix;
+  }
+
+  /**
+   * Normalise the table name by trimming catalog and schema and removing any
+   * quoted identifier characters (",',[,] etc).
+   */
+  public String normaliseTable(String tableName) {
+
+    return normalise.normaliseTable(tableName);
+  }
+
+  /**
+   * Normalise the column name by removing any quoted identifier characters (",',[,] etc).
+   */
+  public String normaliseColumn(String tableName) {
+
+    return normalise.normaliseColumn(tableName);
+  }
+
+  /**
+   * Lower case the table or column name checking for quoted identifiers.
+   */
+  public String lowerName(String tableName) {
+    if (lowerCaseNames && normalise.notQuoted(tableName)) {
+      return tableName.toLowerCase();
+    }
+    return tableName;
+  }
+
+}

src/main/java/com/avaje/ebean/config/DbConstraintNormalise.java

@@ -0,0 +1,79 @@
+package com.avaje.ebean.config;
+
+/**
+ * Used to normalise table and column names which means stripping out
+ * quoted identifier characters and any catalog or schema prefix.
+ */
+public class DbConstraintNormalise {
+
+  protected final String[] quotedIdentifiers;
+
+  protected boolean lowerCaseTables = true;
+
+  protected boolean lowerCaseColumns = true;
+
+  public DbConstraintNormalise() {
+    this.quotedIdentifiers = new String[]{"\"", "'", "[", "]", "`"};
+  }
+
+  /**
+   * Normalise the table name by trimming catalog and schema and removing any
+   * quoted identifier characters (",',[,] etc).
+   */
+  public String normaliseTable(String tableName) {
+
+    tableName = trimQuotes(tableName);
+    int lastPeriod = tableName.lastIndexOf('.');
+    if (lastPeriod > -1) {
+      // trim off catalog and schema prefix
+      tableName = tableName.substring(lastPeriod + 1);
+    }
+    if (lowerCaseTables) {
+      tableName = tableName.toLowerCase();
+    }
+    return tableName;
+  }
+
+  /**
+   * Normalise the column name by removing any quoted identifier characters.
+   */
+  public String normaliseColumn(String columnName) {
+
+    columnName = trimQuotes(columnName);
+    if (lowerCaseColumns) {
+      columnName = columnName.toLowerCase();
+    }
+    return columnName;
+  }
+
+  /**
+   * Trim off the platform quoted identifier quotes like [ ' and ".
+   */
+  public boolean notQuoted(String tableName) {
+
+    // remove quoted identifier characters
+    for (int i = 0; i < quotedIdentifiers.length; i++) {
+      if (tableName.contains(quotedIdentifiers[i])) {
+        return false;
+      }
+    }
+    return true;
+  }
+
+  /**
+   * Trim off the platform quoted identifier quotes like [ ' and ".
+   */
+  public String trimQuotes(String tableName) {
+
+    if (tableName == null) {
+      return "";
+    }
+    // remove quoted identifier characters
+    for (int i = 0; i < quotedIdentifiers.length; i++) {
+      tableName = tableName.replace(quotedIdentifiers[i], "");
+    }
+    return tableName;
+  }
+
+
+}

src/main/java/com/avaje/ebean/config/DbMigrationConfig.java

@@ -0,0 +1,39 @@
+package com.avaje.ebean.config;
+
+/**
+ * Configuration for the DB migration processing.
+ */
+public class DbMigrationConfig {
+
+  /**
+   * Resource path for the migration xml and sql.
+   * Typically you would change 'app' to be a better/more unique.
+   */
+  private String resourcePath = "dbmigration/app";
+
+  /**
+   * Return the resource path for db migrations.
+   */
+  public String getResourcePath() {
+    return resourcePath;
+  }
+
+  /**
+   * Set the resource path for db migrations.
+   * <p>
+   * Typically this would be something like "dbmigration/myapp" where myapp gives it a
+   * unique resource path in the case there are multiple EbeanServer applications in the
+   * single classpath.
+   * </p>
+   */
+  public void setResourcePath(String resourcePath) {
+    this.resourcePath = resourcePath;
+  }
+
+  /**
+   * Load the settings from the PropertiesWrapper.
+   */
+  public void loadSettings(PropertiesWrapper properties) {
+    resourcePath = properties.get("migration.resourcePath", resourcePath);
+  }
+}

src/main/java/com/avaje/ebean/config/NamingConvention.java

@@ -82,8 +82,7 @@ public interface NamingConvention {
   String getPropertyFromColumn(Class<?> beanClass, String dbColumnName);
 
   /**
-   * Return the sequence name given the table name (for DB's that use
-   * sequences).
+   * Return the sequence name given the table name (for DB's that use sequences).
    * <p>
    * Typically you might append "_seq" to the table name as an example.
    * </p>
@@ -99,14 +98,14 @@ public interface NamingConvention {
    * Return true if a prefix should be used building a foreign key name.
    * <p>
    * This by default is true and this works well when the primary key column
-   * names are simply "ID". In this case a prefix (such as "ORDER" and
-   * "CUSTOMER" etc) is added to the foreign key column producing "ORDER_ID" and
-   * "CUSTOMER_ID".
+   * names are simply "id". In this case a prefix (such as "order" and
+   * "customer" etc) is added to the foreign key column producing "order_id" and
+   * "customer_id".
    * </p>
    * <p>
    * This should return false when your primary key columns are the same as the
    * foreign key columns. For example, when the primary key columns are
-   * "ORDER_ID", "CUST_ID" etc ... and they are the same as the foreign key
+   * "order_id", "cust_id" etc ... and they are the same as the foreign key
    * column names.
    * </p>
    */

src/main/java/com/avaje/ebean/config/PersistBatch.java

@@ -36,7 +36,7 @@ public enum PersistBatch {
   INHERIT(false);
 
 
-  boolean forInsert;
+  final boolean forInsert;
 
   PersistBatch(boolean forInsert) {
     this.forInsert = forInsert;

src/main/java/com/avaje/ebean/config/PropertyExpression.java

@@ -27,12 +27,12 @@ final class PropertyExpression {
   /**
    * Used to detect the start of an expression.
    */
-  private static String START = "${";
+  private static final String START = "${";
 
   /**
    * Used to detect the end of an expression.
    */
-  private static String END = "}";
+  private static final String END = "}";
 
   /**
    * Specify the PropertyHolder.
@@ -144,13 +144,7 @@ final class PropertyExpression {
   }
 
   private static boolean isJndiExpression(String exp) {
-    if (exp.startsWith("JNDI:")) {
-      return true;
-    }
-    if (exp.startsWith("jndi:")) {
-      return true;
-    }
-    return false;
+    return exp.startsWith("JNDI:") || exp.startsWith("jndi:");
   }
 
   /**

src/main/java/com/avaje/ebean/config/PropertyMap.java

@@ -16,7 +16,7 @@ public final class PropertyMap implements Serializable {
 
   private static final long serialVersionUID = 1L;
 
-  private LinkedHashMap<String, String> map = new LinkedHashMap<String, String>();
+  private final LinkedHashMap<String, String> map = new LinkedHashMap<String, String>();
 
   public static Properties defaultProperties() {
     PropertyMap propertyMap = PropertyMapLoader.loadGlobalProperties();

src/main/java/com/avaje/ebean/config/PstmtDelegate.java

@@ -1,24 +0,0 @@
-package com.avaje.ebean.config;
-
-import java.sql.PreparedStatement;
-
-/**
- * Unwrap the PreparedStatement to get the specific underlying implementation.
- * <p>
- * This is used to handle specific JDBC driver issues. Typically this means
- * getting the OraclePreparedStatement to handle Oracle specific issues etc.
- * </p>
- * 
- * @author rbygrave
- */
-public interface PstmtDelegate {
-
-  /**
-   * Unwrap the PreparedStatement to get the specific underlying implementation.
-   * 
-   * @param pstmt
-   *          the PreparedStatement coming out of the connection pool
-   * @return the underlying PreparedStatement
-   */
-  PreparedStatement unwrap(PreparedStatement pstmt);
-}

src/main/java/com/avaje/ebean/config/ServerConfig.java

@@ -8,6 +8,9 @@ import com.avaje.ebean.cache.ServerCacheManager;
 import com.avaje.ebean.config.dbplatform.DatabasePlatform;
 import com.avaje.ebean.config.dbplatform.DbEncrypt;
 import com.avaje.ebean.event.*;
+import com.avaje.ebean.event.changelog.ChangeLogListener;
+import com.avaje.ebean.event.changelog.ChangeLogPrepare;
+import com.avaje.ebean.event.changelog.ChangeLogRegister;
 import com.avaje.ebean.meta.MetaInfoManager;
 import com.avaje.ebean.util.ClassUtil;
 import com.fasterxml.jackson.core.JsonFactory;
@@ -70,6 +73,11 @@ public class ServerConfig {
 
   private ContainerConfig containerConfig;
 
+  /**
+   * The underlying properties that were used during configuration.
+   */
+  private Properties properties;
+
   /**
    * The resource directory.
    */
@@ -113,6 +121,12 @@ public class ServerConfig {
    */
   private String classPathReaderClassName;
 
+  /**
+   * This is used to populate @WhoCreated, @WhoModified and
+   * support other audit features (who executed a query etc).
+   */
+  private CurrentUserProvider currentUserProvider;
+
   /** 
    * Config controlling the autofetch behaviour.
    */
@@ -144,6 +158,24 @@ public class ServerConfig {
    */
   private int databaseSequenceBatchSize = 20;
 
+  /**
+   * Suffix appended to the base table to derive the view that contains the union
+   * of the base table and the history table in order to support asOf queries.
+   */
+  private String asOfViewSuffix = "_with_history";
+
+  /**
+   * Column used to support history and 'As of' queries. This column is a timestamp range
+   * or equivalent.
+   */
+  private String asOfSysPeriod = "sys_period";
+
+  /**
+   * Suffix appended to the base table to derive the view that contains the union
+   * of the base table and the history table in order to support asOf queries.
+   */
+  private String historyTableSuffix = "_history";
+
   /**
    * Use for transaction scoped batch mode.
    */
@@ -180,11 +212,6 @@ public class ServerConfig {
   private ExternalTransactionManager externalTransactionManager;
 
   /**
-   * Used to unwrap PreparedStatements to perform JDBC Driver specific functions
-   */
-  private PstmtDelegate pstmtDelegate;
-
-  /** 
    * The data source (if programmatically provided). 
    */
   private DataSource dataSource;
@@ -194,6 +221,11 @@ public class ServerConfig {
    */
   private DataSourceConfig dataSourceConfig = new DataSourceConfig();
 
+  /**
+   * The db migration config (migration resource path etc).
+   */
+  private DbMigrationConfig migrationConfig = new DbMigrationConfig();
+
   /**
    * Set to true if the DataSource uses autoCommit.
    * <p>
@@ -221,11 +253,21 @@ public class ServerConfig {
    */
   private NamingConvention namingConvention = new UnderscoreNamingConvention();
 
+  /**
+   * Naming convention used in DDL generation for primary keys, foreign keys etc.
+   */
+  private DbConstraintNaming constraintNaming = new DbConstraintNaming();
+
   /** 
    * Behaviour of update to include on the change properties. 
    */
   private boolean updateChangesOnly = true;
-  
+
+  /**
+   * Behaviour of updates in JDBC batch to by default include all properties.
+   */
+  private boolean updateAllPropertiesInBatch = true;
+
   /**
    * Default behaviour for updates when cascade save on a O2M or M2M to delete any missing children.
    */
@@ -239,12 +281,24 @@ public class ServerConfig {
 
   private List<BeanFindController> findControllers = new ArrayList<BeanFindController>();
   private List<BeanPersistController> persistControllers = new ArrayList<BeanPersistController>();
+  private List<BeanPostLoad> postLoaders = new ArrayList<BeanPostLoad>();
   private List<BeanPersistListener> persistListeners = new ArrayList<BeanPersistListener>();
   private List<BeanQueryAdapter> queryAdapters = new ArrayList<BeanQueryAdapter>();
   private List<BulkTableEventListener> bulkTableEventListeners = new ArrayList<BulkTableEventListener>();
   private List<ServerConfigStartup> configStartupListeners = new ArrayList<ServerConfigStartup>();
   private List<TransactionEventListener> transactionEventListeners = new ArrayList<TransactionEventListener>();
 
+  /**
+   * By default inserts are included in the change log.
+   */
+  private boolean changeLogIncludeInserts = true;
+
+  private ChangeLogPrepare changeLogPrepare;
+
+  private ChangeLogListener changeLogListener;
+
+  private ChangeLogRegister changeLogRegister;
+
   private EncryptKeyManager encryptKeyManager;
 
   private EncryptDeployManager encryptDeployManager;
@@ -299,6 +353,12 @@ public class ServerConfig {
   private int queryCacheMaxIdleTime = 600;
   private int queryCacheMaxTimeToLive = 60*60*6;
   private Object objectMapper;
+  private boolean diffFlatMode = true;
+
+  /**
+   * Set to true if you want eq("someProperty", null) to generate 1=1 rather than "is null" sql expression.
+   */
+  private boolean expressionEqualsWithNullAsNoop;
 
   /**
    * Construct a Server Configuration for programmatically creating an EbeanServer.
@@ -434,6 +494,22 @@ public class ServerConfig {
     this.defaultServer = defaultServer;
   }
 
+  /**
+   * Return the CurrentUserProvider. This is used to populate @WhoCreated, @WhoModified and
+   * support other audit features (who executed a query etc).
+   */
+  public CurrentUserProvider getCurrentUserProvider() {
+    return currentUserProvider;
+  }
+
+  /**
+   * Set the CurrentUserProvider. This is used to populate @WhoCreated, @WhoModified and
+   * support other audit features (who executed a query etc).
+   */
+  public void setCurrentUserProvider(CurrentUserProvider currentUserProvider) {
+    this.currentUserProvider = currentUserProvider;
+  }
+
   /**
    * Return the PersistBatch mode to use by default at the transaction level.
    * <p>
@@ -461,7 +537,7 @@ public class ServerConfig {
   /**
    * Return the JDBC batch mode to use per save(), delete(), insert() or update() request.
    * <p>
-   * This makes sense when a save() or delete() etc cascades and executes multiple child statements. The best caase
+   * This makes sense when a save() or delete() cascades and executes multiple child statements. The best case
    * for this is when saving a master/parent bean this cascade inserts many detail/child beans.
    * </p>
    * <p>
@@ -579,6 +655,136 @@ public class ServerConfig {
     this.databaseSequenceBatchSize = databaseSequenceBatchSize;
   }
 
+  /**
+   * Return the ChangeLogPrepare.
+   * <p>
+   *   This is used to set user context information to the ChangeSet in the
+   *   foreground thread prior to the logging occurring in a background thread.
+   * </p>
+   */
+  public ChangeLogPrepare getChangeLogPrepare() {
+    return changeLogPrepare;
+  }
+
+  /**
+   * Set the ChangeLogPrepare.
+   * <p>
+   *   This is used to set user context information to the ChangeSet in the
+   *   foreground thread prior to the logging occurring in a background thread.
+   * </p>
+   */
+  public void setChangeLogPrepare(ChangeLogPrepare changeLogPrepare) {
+    this.changeLogPrepare = changeLogPrepare;
+  }
+
+  /**
+   * Return the ChangeLogListener which actually performs the logging of change sets
+   * in the background.
+   */
+  public ChangeLogListener getChangeLogListener() {
+    return changeLogListener;
+  }
+
+  /**
+   * Set the ChangeLogListener which actually performs the logging of change sets
+   * in the background.
+   */
+  public void setChangeLogListener(ChangeLogListener changeLogListener) {
+    this.changeLogListener = changeLogListener;
+  }
+
+  /**
+   * Return the ChangeLogRegister which controls which ChangeLogFilter is used for each
+   * bean type and in this way provide fine grained control over which persist requests
+   * are included in the change log.
+   */
+  public ChangeLogRegister getChangeLogRegister() {
+    return changeLogRegister;
+  }
+
+  /**
+   * Set the ChangeLogRegister which controls which ChangeLogFilter is used for each
+   * bean type and in this way provide fine grained control over which persist requests
+   * are included in the change log.
+   */
+  public void setChangeLogRegister(ChangeLogRegister changeLogRegister) {
+    this.changeLogRegister = changeLogRegister;
+  }
+
+  /**
+   * Return true if inserts should be included in the change log by default.
+   */
+  public boolean isChangeLogIncludeInserts() {
+    return changeLogIncludeInserts;
+  }
+
+  /**
+   * Set if inserts should be included in the change log by default.
+   */
+  public void setChangeLogIncludeInserts(boolean changeLogIncludeInserts) {
+    this.changeLogIncludeInserts = changeLogIncludeInserts;
+  }
+
+  /**
+   * Return the DB migration configuration.
+   */
+  public DbMigrationConfig getMigrationConfig() {
+    return migrationConfig;
+  }
+
+  /**
+   * Set the DB migration configuration.
+   */
+  public void setMigrationConfig(DbMigrationConfig migrationConfig) {
+    this.migrationConfig = migrationConfig;
+  }
+
+  /**
+   * Return the suffix appended to the base table to derive the view that contains the union
+   * of the base table and the history table in order to support asOf queries.
+   */
+  public String getAsOfViewSuffix() {
+    return asOfViewSuffix;
+  }
+
+  /**
+   * Set the suffix appended to the base table to derive the view that contains the union
+   * of the base table and the history table in order to support asOf queries.
+   */
+  public void setAsOfViewSuffix(String asOfViewSuffix) {
+    this.asOfViewSuffix = asOfViewSuffix;
+  }
+
+  /**
+   * Return the database column used to support history and 'As of' queries. This column is a timestamp range
+   * or equivalent.
+   */
+  public String getAsOfSysPeriod() {
+    return asOfSysPeriod;
+  }
+
+  /**
+   * Set the database column used to support history and 'As of' queries. This column is a timestamp range
+   * or equivalent.
+   */
+  public void setAsOfSysPeriod(String asOfSysPeriod) {
+    this.asOfSysPeriod = asOfSysPeriod;
+  }
+
+  /**
+   * Return the history table suffix (defaults to _history).
+   */
+  public String getHistoryTableSuffix() {
+    return historyTableSuffix;
+  }
+
+  /**
+   * Set the history table suffix.
+   */
+  public void setHistoryTableSuffix(String historyTableSuffix) {
+    this.historyTableSuffix = historyTableSuffix;
+  }
+
   /**
    * Return true if we are running in a JTA Transaction manager.
    */
@@ -883,6 +1089,20 @@ public class ServerConfig {
     this.namingConvention = namingConvention;
   }
 
+  /**
+   * Return the constraint naming convention used in DDL generation.
+   */
+  public DbConstraintNaming getConstraintNaming() {
+    return constraintNaming;
+  }
+
+  /**
+   * Set the constraint naming convention used in DDL generation.
+   */
+  public void setConstraintNaming(DbConstraintNaming constraintNaming) {
+    this.constraintNaming = constraintNaming;
+  }
+
   /**
    * Return the configuration for the Autofetch feature.
    */
@@ -897,24 +1117,6 @@ public class ServerConfig {
     this.autofetchConfig = autofetchConfig;
   }
 
-  /**
-   * Return the PreparedStatementDelegate.
-   */
-  public PstmtDelegate getPstmtDelegate() {
-    return pstmtDelegate;
-  }
-
-  /**
-   * Set the PstmtDelegate which can be used to support JDBC driver specific
-   * features.
-   * <p>
-   * Typically this means Oracle JDBC driver specific workarounds.
-   * </p>
-   */
-  public void setPstmtDelegate(PstmtDelegate pstmtDelegate) {
-    this.pstmtDelegate = pstmtDelegate;
-  }
-
   /**
    * Return the DataSource.
    */
@@ -1449,7 +1651,26 @@ public class ServerConfig {
   public void setUpdateChangesOnly(boolean updateChangesOnly) {
     this.updateChangesOnly = updateChangesOnly;
   }
-    
+
+  /**
+   * Returns true if updates in JDBC batch default to include all properties by default.
+   */
+  public boolean isUpdateAllPropertiesInBatch() {
+    return updateAllPropertiesInBatch;
+  }
+
+  /**
+   * Set to false if by default updates in JDBC batch should not include all properties.
+   * <p>
+   *   This mode can be explicitly set per transaction.
+   * </p>
+   *
+   * @see com.avaje.ebean.Transaction#setUpdateAllLoadedProperties(boolean)
+   */
+  public void setUpdateAllPropertiesInBatch(boolean updateAllPropertiesInBatch) {
+    this.updateAllPropertiesInBatch = updateAllPropertiesInBatch;
+  }
+
   /**
    * Return true if updates by default delete missing children when cascading save to a OneToMany or
    * ManyToMany. When not set this defaults to true.
@@ -1564,14 +1785,45 @@ public class ServerConfig {
     persistControllers.add(beanPersistController);
   }
 
+  /**
+   * Register a BeanPostLoad instance.
+   * <p>
+   * Note alternatively you can use {@link #setPostLoaders(List)} to set
+   * all the BeanPostLoad instances.
+   * </p>
+   */
+  public void add(BeanPostLoad postLoad) {
+    postLoaders.add(postLoad);
+  }
+
+  /**
+   * Return the list of BeanFindController instances.
+   */
   public List<BeanFindController> getFindControllers() {
     return findControllers;
   }
 
+  /**
+   * Set the list of BeanFindController instances.
+   */
   public void setFindControllers(List<BeanFindController> findControllers) {
     this.findControllers = findControllers;
   }
 
+  /**
+   * Return the list of BeanPostLoader instances.
+   */
+  public List<BeanPostLoad> getPostLoaders() {
+    return postLoaders;
+  }
+
+  /**
+   * Set the list of BeanPostLoader instances.
+   */
+  public void setPostLoaders(List<BeanPostLoad> postLoaders) {
+    this.postLoaders = postLoaders;
+  }
+
   /**
    * Return the BeanPersistController instances.
    */
@@ -1716,10 +1968,18 @@ public class ServerConfig {
    * Load the settings from the given properties
    */
   public void loadFromProperties(Properties properties) {
+    // keep the properties used for configuration so that these are available for plugins
+    this.properties = properties;
     PropertiesWrapper p = new PropertiesWrapper("ebean", name, properties);
     loadSettings(p);
   }
 
+  /**
+   * Return the properties that we used for configuration and were set via a call to loadFromProperties().
+   */
+  public Properties getProperties() {
+    return properties;
+  }
 
   @SuppressWarnings("unchecked")
   private <T> T createInstance(PropertiesWrapper p, Class<T> pluginType, String key) {
@@ -1751,6 +2011,8 @@ public class ServerConfig {
    */
   protected void loadSettings(PropertiesWrapper p) {
 
+    migrationConfig.loadSettings(p);
+
     namingConvention = createNamingConvention(p, namingConvention);
     if (namingConvention != null) {
       namingConvention.loadFromProperties(p);
@@ -1768,6 +2030,7 @@ public class ServerConfig {
     autoCommitMode = p.getBoolean("autoCommitMode", autoCommitMode);
     useJtaTransactionManager = p.getBoolean("useJtaTransactionManager", useJtaTransactionManager);
 
+    currentUserProvider = createInstance(p, CurrentUserProvider.class, "currentUserProvider");
     disableClasspathSearch = p.getBoolean("disableClasspathSearch", disableClasspathSearch);
     databasePlatform = createInstance(p, DatabasePlatform.class, "databasePlatform");
     encryptKeyManager = createInstance(p, EncryptKeyManager.class, "encryptKeyManager");
@@ -1792,6 +2055,7 @@ public class ServerConfig {
     collectQueryStatsByNode = p.getBoolean("collectQueryStatsByNode", collectQueryStatsByNode);
     collectQueryOrigins = p.getBoolean("collectQueryOrigins", collectQueryOrigins);
 
+    updateAllPropertiesInBatch = p.getBoolean("updateAllPropertiesInBatch", updateAllPropertiesInBatch);
     updateChangesOnly = p.getBoolean("updateChangesOnly", updateChangesOnly);
     
     boolean defaultDeleteMissingChildren = p.getBoolean("defaultDeleteMissingChildren", updatesDeleteMissingChildren);
@@ -1809,6 +2073,12 @@ public class ServerConfig {
 
     persistenceContextScope = PersistenceContextScope.valueOf(p.get("persistenceContextScope", "TRANSACTION"));
 
+    changeLogIncludeInserts = p.getBoolean("changeLogIncludeInserts", changeLogIncludeInserts);
+    expressionEqualsWithNullAsNoop = p.getBoolean("expressionEqualsWithNullAsNoop", expressionEqualsWithNullAsNoop);
+    diffFlatMode = p.getBoolean("diffFlatMode", diffFlatMode);
+    asOfViewSuffix = p.get("asOfViewSuffix", asOfViewSuffix);
+    asOfSysPeriod = p.get("asOfSysPeriod", asOfSysPeriod);
+    historyTableSuffix = p.get("historyTableSuffix", historyTableSuffix);
     dataSourceJndiName = p.get("dataSourceJndiName", dataSourceJndiName);
     databaseSequenceBatchSize = p.getInt("databaseSequenceBatchSize", databaseSequenceBatchSize);
     databaseBooleanTrue = p.get("databaseBooleanTrue", databaseBooleanTrue);
@@ -1898,11 +2168,58 @@ public class ServerConfig {
     return databasePlatform.isDisallowBatchOnCascade() ? PersistBatch.NONE : persistBatchOnCascade;
   }
 
+  /**
+   * Return the Jackson ObjectMapper.
+   * <p>
+   * Note that this is not strongly typed as Jackson ObjectMapper is an optional dependency.
+   * </p>
+   */
   public Object getObjectMapper() {
     return objectMapper;
   }
 
+  /**
+   * Set the Jackson ObjectMapper.
+   * <p>
+   * Note that this is not strongly typed as Jackson ObjectMapper is an optional dependency.
+   * </p>
+   */
   public void setObjectMapper(Object objectMapper) {
     this.objectMapper = objectMapper;
   }
+
+  /**
+   * Return true if diff should return flat properties with dot notation rather than
+   * embedded beans or reference beans (when the associated bean id is different).
+   */
+  public boolean isDiffFlatMode() {
+    return diffFlatMode;
+  }
+
+  /**
+   * Set to true if diff should return flat properties with dot notation rather than
+   * embedded beans or reference beans (when the associated bean id is different).
+   */
+  public void setDiffFlatMode(boolean diffFlatMode) {
+    this.diffFlatMode = diffFlatMode;
+  }
+
+  /**
+   * Return true if eq("someProperty", null) should to generate "1=1" rather than "is null" sql expression.
+   */
+  public boolean isExpressionEqualsWithNullAsNoop() {
+    return expressionEqualsWithNullAsNoop;
+  }
+
+  /**
+   * Set to true if you want eq("someProperty", null) to generate "1=1" rather than "is null" sql expression.
+   * <p>
+   *   Setting this to true has the effect that eq(propertyName, value), ieq(propertyName, value) and
+   *   ne(propertyName, value) have no effect when the value is null. The expression factory adds a NoopExpression
+   *   which will add "1=1" into the SQL rather than "is null".
+   * </p>
+   */
+  public void setExpressionEqualsWithNullAsNoop(boolean expressionEqualsWithNullAsNoop) {
+    this.expressionEqualsWithNullAsNoop = expressionEqualsWithNullAsNoop;
+  }
 }

src/main/java/com/avaje/ebean/config/UnderscoreNamingConvention.java

@@ -3,23 +3,26 @@ package com.avaje.ebean.config;
 /**
  * Converts between Camel Case and Underscore based names for both table and
  * column names (and is the default naming convention in Ebean).
- * 
+ *
  * @author emcgreal
  * @author rbygrave
  */
 public class UnderscoreNamingConvention extends AbstractNamingConvention {
 
-  /** Force toUnderscore to return in upper case. */
+  /**
+   * Force toUnderscore to return in upper case.
+   */
   private boolean forceUpperCase = false;
 
-  /** The digits compressed. */
+  /**
+   * The digits compressed.
+   */
   private boolean digitsCompressed = true;
 
   /**
    * Create with a given sequence format.
-   * 
-   * @param sequenceFormat
-   *          the sequence format
+   *
+   * @param sequenceFormat the sequence format
    */
   public UnderscoreNamingConvention(String sequenceFormat) {
     super(sequenceFormat);
@@ -34,39 +37,30 @@ public class UnderscoreNamingConvention extends AbstractNamingConvention {
 
   /**
    * Returns the last part of the class name.
-   * 
-   * @param beanClass
-   *          the bean class
-   * 
+   *
+   * @param beanClass the bean class
    * @return the table name from class
    */
   public TableName getTableNameByConvention(Class<?> beanClass) {
 
-    return new TableName(getCatalog(),
-        getSchema(),
-        toUnderscoreFromCamel(beanClass.getSimpleName()));
+    return new TableName(getCatalog(), getSchema(), toUnderscoreFromCamel(beanClass.getSimpleName()));
   }
 
   /**
    * Converts Camel case property name to underscore based column name.
-   * 
+   *
    * @return the column from property
    */
-  public String getColumnFromProperty(Class<?> beanClass, String propertyName) {// Field
-                                                                                // field)
-                                                                                // {
+  public String getColumnFromProperty(Class<?> beanClass, String propertyName) {
 
     return toUnderscoreFromCamel(propertyName);
   }
 
   /**
    * Converts underscore based column name to Camel case property name.
-   * 
-   * @param beanClass
-   *          the bean class
-   * @param dbColumnName
-   *          the db column name
-   * 
+   *
+   * @param beanClass    the bean class
+   * @param dbColumnName the db column name
    * @return the property from column
    */
   public String getPropertyFromColumn(Class<?> beanClass, String dbColumnName) {
@@ -110,7 +104,7 @@ public class UnderscoreNamingConvention extends AbstractNamingConvention {
   protected String toUnderscoreFromCamel(String camelCase) {
 
     int lastUpper = -1;
-    StringBuffer sb = new StringBuffer();
+    StringBuilder sb = new StringBuilder(camelCase.length()+4);
     for (int i = 0; i < camelCase.length(); i++) {
       char c = camelCase.charAt(i);
 
@@ -144,16 +138,11 @@ public class UnderscoreNamingConvention extends AbstractNamingConvention {
   }
 
   /**
-   * To camel from underscore.
-   * 
-   * @param underscore
-   *          the underscore
-   * 
-   * @return the string
+   * Convert and return the from string from underscore to camel case.
    */
   protected String toCamelFromUnderscore(String underscore) {
 
-    StringBuffer result = new StringBuffer();
+    StringBuilder result = new StringBuilder(underscore.length());
     String[] vals = underscore.split("_");
 
     for (int i = 0; i < vals.length; i++) {

src/main/java/com/avaje/ebean/config/dbplatform/DB2Platform.java

@@ -5,6 +5,7 @@ import java.sql.Types;
 import javax.sql.DataSource;
 
 import com.avaje.ebean.BackgroundExecutor;
+import com.avaje.ebean.dbmigration.ddlgeneration.platform.DB2Ddl;
 
 /**
  * DB2 specific platform.
@@ -14,10 +15,11 @@ public class DB2Platform extends DatabasePlatform {
   public DB2Platform() {
     super();
     this.name = "db2";
-
-    // only support getGeneratedKeys with non-batch JDBC
-    // so generally use SEQUENCE instead for H2
+    this.maxTableNameLength = 18;
+    this.maxConstraintNameLength = 18;
     this.sqlLimiter = new Db2SqlLimiter();
+    this.platformDdl = new DB2Ddl(dbTypeMap, dbIdentity);
+
     this.dbIdentity.setSupportsGetGeneratedKeys(true);
     this.dbIdentity.setSupportsSequence(true);
 
@@ -25,8 +27,6 @@ public class DB2Platform extends DatabasePlatform {
     dbTypeMap.put(Types.REAL, new DbType("real"));
     dbTypeMap.put(Types.TINYINT, new DbType("smallint"));
     dbTypeMap.put(Types.DECIMAL, new DbType("decimal", 15));
-
-    this.dbDdlSyntax.setIdentity("generated by default as identity");
   }
 
   /**

src/main/java/com/avaje/ebean/config/dbplatform/DatabasePlatform.java

@@ -7,6 +7,9 @@ import javax.sql.DataSource;
 import com.avaje.ebean.BackgroundExecutor;
 import com.avaje.ebean.Query;
 
+import com.avaje.ebean.config.ServerConfig;
+import com.avaje.ebean.dbmigration.ddlgeneration.DdlHandler;
+import com.avaje.ebean.dbmigration.ddlgeneration.platform.PlatformDdl;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -17,6 +20,7 @@ public class DatabasePlatform {
 
   private static final Logger logger = LoggerFactory.getLogger(DatabasePlatform.class);
 
+
   /**
    * Behavior used when ending a query only transaction (at read committed isolation level).
    */
@@ -70,16 +74,16 @@ public class DatabasePlatform {
    */
   protected DbTypeMap dbTypeMap = new DbTypeMap();
 
-  /** 
-   * DB specific DDL syntax. 
-   */
-  protected DbDdlSyntax dbDdlSyntax = new DbDdlSyntax();
-
-  /** 
+  /**
    * Defines DB identity/sequence features. 
    */
   protected DbIdentity dbIdentity = new DbIdentity();
 
+  /**
+   * The history support for this database platform.
+   */
+  protected DbHistorySupport historySupport;
+
   /** 
    * The JDBC type to map booleans to (by default). 
    */
@@ -140,6 +144,20 @@ public class DatabasePlatform {
    */
   protected boolean disallowBatchOnCascade;
 
+  protected PlatformDdl platformDdl;
+
+  /**
+   * The maximum length of table names - used specifically when derived
+   * default table names for intersection tables.
+   */
+  protected int maxTableNameLength = 60;
+
+  /**
+   * A value of 60 is a reasonable default for all databases except
+   * Oracle (limited to 30) and DB2 (limited to 18).
+   */
+  protected int maxConstraintNameLength = 60;
+
   /**
    * Instantiates a new database platform.
    */
@@ -152,13 +170,42 @@ public class DatabasePlatform {
    * "generic" is returned when no specific database platform has been set or
    * found.
    * </p>
-   * 
-   * @return the name
    */
   public String getName() {
     return name;
   }
 
+  /**
+   * Return the maximum table name length.
+   * <p>
+   * This is used when deriving names of intersection tables.
+   * </p>
+   */
+  public int getMaxTableNameLength() {
+    return maxTableNameLength;
+  }
+
+  /**
+   * Return the maximum constraint name allowed for the platform.
+   */
+  public int getMaxConstraintNameLength() {
+    return maxConstraintNameLength;
+  }
+
+  /**
+   * Return the platform specific DDL.
+   */
+  public PlatformDdl getPlatformDdl() {
+    return platformDdl;
+  }
+
+  /**
+   * Create and return a DDL handler for generating DDL scripts.
+   */
+  public DdlHandler createDdlHandler(ServerConfig serverConfig) {
+    return platformDdl.createDdlHandler(serverConfig);
+  }
+
   /**
    * Return true if the JDBC driver does not allow additional queries to execute
    * when a resultSet is being 'streamed' as is the case with findEach() etc.
@@ -215,6 +262,20 @@ public class DatabasePlatform {
     this.dbEncrypt = dbEncrypt;
   }
 
+  /**
+   * Return the history support for this database platform.
+   */
+  public DbHistorySupport getHistorySupport() {
+    return historySupport;
+  }
+
+  /**
+   * Set the history support for this database platform.
+   */
+  public void setHistorySupport(DbHistorySupport historySupport) {
+    this.historySupport = historySupport;
+  }
+
   /**
    * Return the mapping of JDBC to DB types.
    * 
@@ -224,15 +285,6 @@ public class DatabasePlatform {
     return dbTypeMap;
   }
 
-  /**
-   * Return the DDL syntax for this platform.
-   * 
-   * @return the db ddl syntax
-   */
-  public DbDdlSyntax getDbDdlSyntax() {
-    return dbDdlSyntax;
-  }
-
   /**
    * Return the column alias prefix.
    */
@@ -442,22 +494,4 @@ public class DatabasePlatform {
     return disallowBatchOnCascade;
   }
 
-  /**
-   * Generate and return the create sequence DDL.
-   */
-  public String ddlCreateSequence(String sequenceName, int initialValue, int allocationSize) {
-
-    StringBuilder sb = new StringBuilder("create sequence ");
-    sb.append(sequenceName);
-    if (initialValue > 1) {
-      sb.append(" start with ").append(initialValue);
-    }
-    if (allocationSize > 0 && allocationSize != 50) {
-      // at this stage ignoring allocationSize 50 as this is the 'default' and
-      // not consistent with the way Ebean batch fetches sequence values
-      sb.append(" increment by ").append(allocationSize);
-    }
-    sb.append(";");
-    return sb.toString();
-  }
 }

src/main/java/com/avaje/ebean/config/dbplatform/DbDdlSyntax.java

@@ -1,333 +0,0 @@
-package com.avaje.ebean.config.dbplatform;
-
-import com.avaje.ebean.config.TableName;
-
-/**
- * Used to support DB specific syntax for DDL generation.
- */
-public class DbDdlSyntax {
-
-  protected boolean renderIndexForFkey = true;
-
-  protected boolean inlinePrimaryKeyConstraint = false;
-
-  protected boolean addOneToOneUniqueContraint = true;
-
-  protected int maxConstraintNameLength = 32;
-
-  protected int columnNameWidth = 25;
-
-  /**
-   * Flag set when we want to disable constraints on each table (rather than globally).
-   */
-  protected boolean dropKeyConstraints;
-
-  protected String dropTableCascade;
-  protected String dropIfExists;
-
-  protected String newLine = "\n";
-
-  protected String identity = "auto_increment";
-  protected String identitySuffix = "";
-
-  protected String pkPrefix = "pk_";
-
-  protected String disableReferentialIntegrity;
-  protected String enableReferentialIntegrity;
-
-  protected String foreignKeySuffix;
-
-  /**
-   * Return the primary key name for a given bean descriptor.
-   */
-  public String getPrimaryKeyName(String tableName) {
-
-    String pk = pkPrefix + tableName;
-    if (pk.length() > maxConstraintNameLength) {
-      // need to trim the primary key name
-      pk = pk.substring(0, maxConstraintNameLength);
-    }
-    return pk;
-  }
-
-  /**
-   * Return the column definition for an identity column.
-   */
-  public String getIdentityColumnDefn(String columnDefn) {
-    String identity = getIdentity();
-    if (identity != null && identity.length() > 0) {
-      return columnDefn+" "+identity;
-    }
-    return columnDefn;
-  }
-  
-  /**
-   * Return the identity clause for DB's that have identities.
-   */
-  public String getIdentity() {
-    return identity;
-  }
-
-  /**
-   * Set the identity clause.
-   */
-  public void setIdentity(String identity) {
-    this.identity = identity;
-  }
-
-  /**
-   * Typically returns empty string but for SQLite and perhaps others
-   * the Identity/AutoIncrement clause comes after the primary key clause.
-   */
-  public String getIdentitySuffix() {
-    return identitySuffix;
-  }
-
-  /**
-   * Set the identity clause that would appear after the primary key clause.
-   * <p>
-   * Only used for SQLite at this stage.
-   * </p>
-   */
-  public void setIdentitySuffix(String identitySuffix) {
-    this.identitySuffix = identitySuffix;
-  }
-
-  /**
-   * Return the width for padding whitespace after column names.
-   */
-  public int getColumnNameWidth() {
-    return columnNameWidth;
-  }
-
-  /**
-   * Set the amount of padding to write after the column name.
-   */
-  public void setColumnNameWidth(int columnNameWidth) {
-    this.columnNameWidth = columnNameWidth;
-  }
-
-  /**
-   * Return the new line character.
-   */
-  public String getNewLine() {
-    return newLine;
-  }
-
-  /**
-   * Set the new line character.
-   */
-  public void setNewLine(String newLine) {
-    this.newLine = newLine;
-  }
-
-  /**
-   * Return the prefix used in naming primary keys.
-   */
-  public String getPkPrefix() {
-    return pkPrefix;
-  }
-
-  /**
-   * Set the prefix used in naming primary keys.
-   */
-  public void setPkPrefix(String pkPrefix) {
-    this.pkPrefix = pkPrefix;
-  }
-
-  /**
-   * Return the DB specific command to disable referential integrity
-   */
-  public String getDisableReferentialIntegrity() {
-    return disableReferentialIntegrity;
-  }
-
-  /**
-   * Set the DB specific command to disable referential integrity
-   */
-  public void setDisableReferentialIntegrity(String disableReferentialIntegrity) {
-    this.disableReferentialIntegrity = disableReferentialIntegrity;
-  }
-
-  /**
-   * Return the DB specific command to enable referential integrity
-   */
-  public String getEnableReferentialIntegrity() {
-    return enableReferentialIntegrity;
-  }
-
-  /**
-   * Set the DB specific command to enable referential integrity
-   */
-  public void setEnableReferentialIntegrity(String enableReferentialIntegrity) {
-    this.enableReferentialIntegrity = enableReferentialIntegrity;
-  }
-
-  /**
-   * Return true to is constraints are disabled on each table.
-   */
-  public boolean isDropKeyConstraints() {
-    return dropKeyConstraints;
-  }
-
-  /**
-   * Return some DDL to disable constraints on the given table.
-   */
-  public String dropKeyConstraintPrefix(String tableName, String fkName) {
-    return null;
-  }
-
-  /**
-   * Return true if indexes should be created for the foreign keys.
-   */
-  public boolean isRenderIndexForFkey() {
-    return renderIndexForFkey;
-  }
-
-  /**
-   * Set whether indexes should be created for the foreign keys.
-   */
-  public void setRenderIndexForFkey(boolean renderIndexForFkey) {
-    this.renderIndexForFkey = renderIndexForFkey;
-  }
-
-  /**
-   * Typically returns IF EXISTS (if that is supported by the database platform)
-   * or null.
-   */
-  public String getDropIfExists() {
-    return dropIfExists;
-  }
-
-  /**
-   * Set the IF EXISTS clause for dropping tables if that is supported by the
-   * database platform.
-   */
-  public void setDropIfExists(String dropIfExists) {
-    this.dropIfExists = dropIfExists;
-  }
-
-  /**
-   * Return prefix text that goes before drop table.
-   */
-  public String dropTablePrefix(String tableName) {
-    return "";
-  }
-
-  /**
-   * Return the cascade option for the drop table command.
-   */
-  public String getDropTableCascade() {
-    return dropTableCascade;
-  }
-
-  /**
-   * Set the cascade option for the drop table command.
-   */
-  public void setDropTableCascade(String dropTableCascade) {
-    this.dropTableCascade = dropTableCascade;
-  }
-
-  /**
-   * Return the foreign key suffix.
-   */
-  public String getForeignKeySuffix() {
-    return foreignKeySuffix;
-  }
-
-  /**
-   * Set the foreign key suffix.
-   */
-  public void setForeignKeySuffix(String foreignKeySuffix) {
-    this.foreignKeySuffix = foreignKeySuffix;
-  }
-
-  /**
-   * Return the maximum length that constraint names can be for this database.
-   */
-  public int getMaxConstraintNameLength() {
-    return maxConstraintNameLength;
-  }
-
-  /**
-   * Set the maximum length that constraint names can be for this database.
-   */
-  public void setMaxConstraintNameLength(int maxFkeyLength) {
-    this.maxConstraintNameLength = maxFkeyLength;
-  }
-
-  /**
-   * Return true if imported side of OneToOne's should have unique constraints
-   * generated.
-   */
-  public boolean isAddOneToOneUniqueContraint() {
-    return addOneToOneUniqueContraint;
-  }
-
-  /**
-   * Set to false for DB's that don't want both a unique and index on the
-   * imported OneToOne.
-   */
-  public void setAddOneToOneUniqueContraint(boolean addOneToOneUniqueContraint) {
-    this.addOneToOneUniqueContraint = addOneToOneUniqueContraint;
-  }
-
-  /**
-   * Return true if primary key constraints should be inlined when they are a
-   * single column.
-   */
-  public boolean isInlinePrimaryKeyConstraint() {
-    return inlinePrimaryKeyConstraint;
-  }
-
-  /**
-   * Set whether to inline primary key constraints.
-   */
-  public void setInlinePrimaryKeyConstraint(boolean inlinePrimaryKeyConstraint) {
-    this.inlinePrimaryKeyConstraint = inlinePrimaryKeyConstraint;
-  }
-
-  /**
-   * Builds and returns a fully index name.
-   */
-  public String getIndexName(String table, String propName, int ixCount) {
-
-
-    StringBuilder buffer = new StringBuilder(30);
-    buffer.append("ix_").append(TableName.parse(table));
-    buffer.append("_").append(propName);
-
-    addSuffix(buffer, ixCount);
-
-    return buffer.toString();
-  }
-
-  /**
-   * Builds and returns a fully qualified foreign key constraint name.
-   */
-  public String getForeignKeyName(String table, String propName, int fkCount) {
-
-    StringBuilder buffer = new StringBuilder(30);
-    buffer.append("fk_").append(TableName.parse(table));
-    buffer.append("_").append(propName);
-
-    addSuffix(buffer, fkCount);
-
-    return buffer.toString();
-  }
-
-  /**
-   * Adds the suffix.
-   */
-  protected void addSuffix(StringBuilder buffer, int count) {
-    String suffixNr = Integer.toString(count);
-    int suffixLen = suffixNr.length() + 1;
-
-    if (buffer.length() + suffixLen > maxConstraintNameLength) {
-      buffer.setLength(maxConstraintNameLength - suffixLen);
-    }
-    buffer.append("_");
-    buffer.append(suffixNr);
-  }
-
-}

src/main/java/com/avaje/ebean/config/dbplatform/DbHistorySupport.java

@@ -0,0 +1,64 @@
+package com.avaje.ebean.config.dbplatform;
+
+/**
+ * History support for the database platform.
+ */
+public interface DbHistorySupport {
+
+  /**
+   * Return true if the 'As of' predicate is part of the from clause
+   * (more standard sql2011). So true for Oracle total recall and false
+   * for Postgres and MySql (where we use views and history tables).
+   */
+  boolean isBindWithFromClause();
+
+  /**
+   * Return the number of columns bound in a 'As Of' predicate.
+   * <p>
+   * This is 1 for more standard sql2011 style and Postgres which has the
+   * special range type and 2 for view based solutions with 2 columns such as
+   * MySql.
+   * </p>
+   */
+  int getBindCount();
+
+  /**
+   * For sql2011 style this ignores the passed in view suffix and returns something
+   * like the ' as of timestamp ?' clause to be appended after the base table name.
+   *
+   * @param asOfViewSuffix the configured view suffix (typically "_with_history").
+   * @return The suffix appended after the base table name in the from and join clauses.
+   */
+  String getAsOfViewSuffix(String asOfViewSuffix);
+
+  /**
+   * Return the 'versions between timestamp' suffix.
+   */
+  String getVersionsBetweenSuffix(String asOfViewSuffix);
+
+  /**
+   * Return the 'as of' predicate added for the given table alias.
+   *
+   * @param tableAlias The table alias this predicate is added for
+   * @param sysPeriod  The name of the 'sys_period' column used for effective date time range.
+   * @return The predicate containing a single ? bind parameter which will be bound to the 'as at' timestamp value
+   */
+  String getAsOfPredicate(String tableAlias, String sysPeriod);
+
+  /**
+   * Return the column for the system period lower bound that will be included in findVersions() queries.
+   *
+   * @param tableAlias the table alias which will typically be 't0'
+   * @param sysPeriod  the name of the sys_period column
+   */
+  String getSysPeriodLower(String tableAlias, String sysPeriod);
+
+  /**
+   * Return the column for the system period upper bound that will be included in findVersions() queries.
+   *
+   * @param tableAlias the table alias which will typically be 't0'
+   * @param sysPeriod  the name of the sys_period column
+   */
+  String getSysPeriodUpper(String tableAlias, String sysPeriod);
+
+}

src/main/java/com/avaje/ebean/config/dbplatform/DbIdentity.java

@@ -1,5 +1,7 @@
 package com.avaje.ebean.config.dbplatform;
 
+import com.avaje.ebean.dbmigration.migration.IdentityType;
+
 /**
  * Defines the identity/sequence behaviour for the database.
  */
@@ -114,4 +116,28 @@ public class DbIdentity {
     this.idType = idType;
   }
 
+  /**
+   * Determine the id type to use based on requested identityType and
+   * the support for that in the database platform.
+   */
+  public IdType useIdentityType(IdentityType identityType) {
+
+    if (identityType == null) {
+      // use the default
+      return idType;
+    }
+    switch (identityType) {
+      case GENERATOR:
+        return IdType.GENERATOR;
+      case EXTERNAL:
+        return IdType.EXTERNAL;
+      case SEQUENCE:
+        return supportsSequence ? IdType.SEQUENCE : idType;
+      case IDENTITY:
+        return supportsIdentity ? IdType.IDENTITY : idType;
+    }
+
+    // use the default
+    return idType;
+  }
 }

src/main/java/com/avaje/ebean/config/dbplatform/DbPlatformName.java

@@ -0,0 +1,47 @@
+package com.avaje.ebean.config.dbplatform;
+
+/**
+ * Built in supported platforms.
+ */
+public enum DbPlatformName {
+
+  /**
+   * Generic base platform configured via properties or code.
+   */
+  GENERIC,
+
+  /**
+   * H2.
+   */
+  H2,
+
+  /**
+   * Postgres.
+   */
+  POSTGRES,
+
+  /**
+   * MySql.
+   */
+  MYSQL,
+
+  /**
+   * Oracle.
+   */
+  ORACLE,
+
+  /**
+   * Microsoft SQL Server.
+   */
+  SQLSERVER,
+
+  /**
+   * DB2.
+   */
+  DB2,
+
+  /**
+   * SQLite.
+   */
+  SQLITE
+}

src/main/java/com/avaje/ebean/config/dbplatform/DbStandardHistorySupport.java

@@ -0,0 +1,32 @@
+package com.avaje.ebean.config.dbplatform;
+
+/**
+ * SQL2011 based history support using 'as of timestamp' type clause appended as part of the the from or join clause.
+ */
+public abstract class DbStandardHistorySupport implements DbHistorySupport {
+
+  /**
+   * Return true as with sql2011 the 'as of timestamp' clause included in from or join clause.
+   */
+  @Override
+  public boolean isBindWithFromClause() {
+    return true;
+  }
+
+  /**
+   * Return 1 as the bind count (not 2 for effective start and effective end columns).
+   */
+  @Override
+  public int getBindCount() {
+    return 1;
+  }
+
+  /**
+   * Return null - not used for sql2011 based history.
+   */
+  @Override
+  public String getAsOfPredicate(String tableAlias, String sysPeriod) {
+    // not used for sql2011 based history
+    return null;
+  }
+}

src/main/java/com/avaje/ebean/config/dbplatform/DbTypeMap.java

@@ -9,16 +9,80 @@ import java.util.Map;
  */
 public class DbTypeMap {
 
+  private static final DbType JSON_CLOB_PLACEHOLDER = new DbType("jsonClobPlaceholder");
+  private static final DbType JSON_BLOB_PLACEHOLDER = new DbType("jsonBlobPlaceholder");
+  private static final DbType JSON_VARCHAR_PLACEHOLDER = new DbType("jsonVarcharPlaceholder");
+
+  /**
+   * A map to reverse lookup the type by name.
+   * <p>
+   * Used when converting from logical types to platform types which we
+   * want to do with 2 phase DDL generation.
+   */
+  static Map<String, Integer> lookup = new HashMap<String, Integer>();
+
+  static {
+    lookup.put("BOOLEAN", Types.BOOLEAN);
+    lookup.put("BIT", Types.BIT);
+    lookup.put("INTEGER", Types.INTEGER);
+    lookup.put("BIGINT", Types.BIGINT);
+    lookup.put("REAL", Types.REAL);
+    // Float is most common REAL mapping to have that as well
+    lookup.put("FLOAT", Types.REAL);
+
+    lookup.put("DOUBLE", Types.DOUBLE);
+    lookup.put("SMALLINT", Types.SMALLINT);
+    lookup.put("TINYINT", Types.TINYINT);
+    lookup.put("DECIMAL", Types.DECIMAL);
+    lookup.put("VARCHAR", Types.VARCHAR);
+    // VARCHAR2 - extra for Oracle specific column definition
+    lookup.put("VARCHAR2", Types.VARCHAR);
+    lookup.put("CHAR", Types.CHAR);
+    lookup.put("BLOB", Types.BLOB);
+    lookup.put("CLOB", Types.CLOB);
+
+    lookup.put("LONGVARBINARY", Types.LONGVARBINARY);
+    lookup.put("LONGVARCHAR", Types.LONGVARCHAR);
+    lookup.put("VARBINARY", Types.VARBINARY);
+    lookup.put("BINARY", Types.BINARY);
+    lookup.put("DATE", Types.DATE);
+    lookup.put("TIME", Types.TIME);
+    lookup.put("TIMESTAMP", Types.TIMESTAMP);
+
+    // Not standard java.sql.Types
+    // logical JSON storage types
+    lookup.put("JSON", DbType.JSON);
+    lookup.put("JSONB", DbType.JSONB);
+    lookup.put("JSONCLOB", DbType.JSONClob);
+    lookup.put("JSONBLOB", DbType.JSONBlob);
+    lookup.put("JSONVARCHAR", DbType.JSONVarchar);
+  }
+
+
   private final Map<Integer, DbType> typeMap = new HashMap<Integer, DbType>();
 
+  /**
+   * Return the DbTypeMap with standard (not platform specific) types.
+   *
+   * This has some extended JSON types (JSON, JSONB, JSONVarchar, JSONClob, JSONBlob).
+   * These types get translated to specific database platform types during DDL generation.
+   */
+  public static DbTypeMap logicalTypes() {
+    return new DbTypeMap(true);
+  }
+
   public DbTypeMap() {
-    loadDefaults();
+    loadDefaults(false);
+  }
+
+  private DbTypeMap(boolean logicalTypes) {
+    loadDefaults(logicalTypes);
   }
 
   /**
    * Load the standard types. These can be overridden by DB specific platform.
    */
-  private void loadDefaults() {
+  private void loadDefaults(boolean logicalTypes) {
 
     put(Types.BOOLEAN, new DbType("boolean"));
     put(Types.BIT, new DbType("bit"));
@@ -37,11 +101,22 @@ public class DbTypeMap {
     put(Types.BLOB, new DbType("blob"));
     put(Types.CLOB, new DbType("clob"));
 
-    put(DbType.JSON, new DbType("clob")); // Postgres maps this to JSON
-    put(DbType.JSONB, new DbType("clob")); // Postgres maps this to JSONB
-    put(DbType.JSONClob, new DbType("clob"));
-    put(DbType.JSONBlob, new DbType("blob"));
-    put(DbType.JSONVarchar, new DbType("varchar", 1000));
+    if (logicalTypes) {
+      // keep it logical for 2 layer DDL generation
+      put(DbType.HSTORE, new DbType("hstore"));
+      put(DbType.JSON, new DbType("json"));
+      put(DbType.JSONB, new DbType("jsonb"));
+      put(DbType.JSONClob, new DbType("jsonclob"));
+      put(DbType.JSONBlob, new DbType("jsonblob"));
+      put(DbType.JSONVarchar, new DbType("jsonvarchar", 1000));
+
+    } else {
+      put(DbType.JSON, JSON_CLOB_PLACEHOLDER); // Postgres maps this to JSON
+      put(DbType.JSONB, JSON_CLOB_PLACEHOLDER); // Postgres maps this to JSONB
+      put(DbType.JSONClob, JSON_CLOB_PLACEHOLDER);
+      put(DbType.JSONBlob, JSON_BLOB_PLACEHOLDER);
+      put(DbType.JSONVarchar, JSON_VARCHAR_PLACEHOLDER);
+    }
 
     put(Types.LONGVARBINARY, new DbType("longvarbinary"));
     put(Types.LONGVARCHAR, new DbType("lonvarchar"));
@@ -54,24 +129,58 @@ public class DbTypeMap {
 
   }
 
+  /**
+   * Lookup the platform specific DbType given the standard sql type name.
+   */
+  public DbType lookup(String name) {
+    name = name.trim().toUpperCase();
+    Integer typeKey = lookup.get(name);
+    if (typeKey == null) {
+      throw new IllegalArgumentException("Unknown type [" + name + "] - not standard sql type");
+    }
+    // handle JSON types mapped to clob, blob and varchar
+    switch (typeKey) {
+      case DbType.JSONBlob:
+        return get(Types.BLOB);
+      case DbType.JSONClob:
+        return get(Types.CLOB);
+      case DbType.JSONVarchar:
+        return get(Types.VARCHAR);
+      case DbType.JSON:
+        return getJsonType(DbType.JSON);
+      case DbType.JSONB:
+        return getJsonType(DbType.JSONB);
+      default:
+        return get(typeKey);
+    }
+  }
+
+  private DbType getJsonType(int type) {
+    DbType dbType = get(type);
+    if (dbType == JSON_CLOB_PLACEHOLDER) {
+      return get(Types.CLOB);
+    }
+    if (dbType == JSON_BLOB_PLACEHOLDER) {
+      return get(Types.BLOB);
+    }
+    if (dbType == JSON_VARCHAR_PLACEHOLDER) {
+      return get(Types.VARCHAR);
+    }
+    // Postgres has specific type
+    return get(type);
+  }
+
   /**
    * Override the type for a given JDBC type.
    */
   public void put(int jdbcType, DbType dbType) {
-    typeMap.put(Integer.valueOf(jdbcType), dbType);
+    typeMap.put(jdbcType, dbType);
   }
 
   /**
    * Return the type for a given jdbc type.
    */
   public DbType get(int jdbcType) {
-
-    DbType dbType = typeMap.get(Integer.valueOf(jdbcType));
-    if (dbType == null) {
-      String m = "No DB type for JDBC type " + jdbcType;
-      throw new RuntimeException(m);
-    }
-
-    return dbType;
+    return typeMap.get(jdbcType);
   }
 }

src/main/java/com/avaje/ebean/config/dbplatform/DbViewHistorySupport.java

@@ -0,0 +1,82 @@
+package com.avaje.ebean.config.dbplatform;
+
+/**
+ * Database view based implementation of DbHistorySupport.
+ * <p>
+ * These implementations have explicit history tables, a view to union the
+ * base table and history table and triggers to maintain the history.
+ * </p>
+ */
+public abstract class DbViewHistorySupport implements DbHistorySupport {
+
+  /**
+   * Return false for view based implementations where we append extra 'as of' predicates to the end.
+   */
+  @Override
+  public boolean isBindWithFromClause() {
+    return false;
+  }
+
+  /**
+   * Returns the configured view suffix.
+   *
+   * @param asOfViewSuffix the configured view suffix (typically "_with_history").
+   */
+  @Override
+  public String getAsOfViewSuffix(String asOfViewSuffix) {
+    // just return the configured suffix
+    return asOfViewSuffix;
+  }
+
+  /**
+   * Returns the configured view suffix (same as getAsOfViewSuffix()).
+   *
+   * @param asOfViewSuffix the configured view suffix (typically "_with_history").
+   */
+  @Override
+  public String getVersionsBetweenSuffix(String asOfViewSuffix) {
+    // just return the configured asOfViewSuffix (using the view for versions between query)
+    return asOfViewSuffix;
+  }
+
+  /**
+   * Return 2 if we have effective start and effective end as 2 columns.
+   * Note that for postgres we can use a single range type so that returns 1.
+   */
+  @Override
+  public int getBindCount() {
+    return 2;
+  }
+
+  /**
+   * Return the 'as of' predicate clause appended to the end of the normal query predicates.
+   */
+  @Override
+  public String getAsOfPredicate(String asOfTableAlias, String asOfSysPeriod) {
+
+    // (sys_period_start < ? and (sys_period_end is null or sys_period_end > ?));
+    return "(" + asOfTableAlias + "." + asOfSysPeriod + "_start" + " < ? and (" + asOfTableAlias + "." + asOfSysPeriod + "_end" + " is null or " + asOfTableAlias + "." + asOfSysPeriod + "_end" + " > ?))";
+  }
+
+  /**
+   * Return the lower bound column prepended with the table alias.
+   *
+   * @param tableAlias the table alias
+   * @param sysPeriod  the name of the sys_period column
+   */
+  @Override
+  public String getSysPeriodLower(String tableAlias, String sysPeriod) {
+    return tableAlias + "." + sysPeriod + "_start";
+  }
+
+  /**
+   * Return the upper bound column prepended with the table alias.
+   *
+   * @param tableAlias the table alias
+   * @param sysPeriod  the name of the sys_period column
+   */
+  @Override
+  public String getSysPeriodUpper(String tableAlias, String sysPeriod) {
+    return tableAlias + "." + sysPeriod + "_end";
+  }
+}

src/main/java/com/avaje/ebean/config/dbplatform/H2Platform.java

@@ -1,6 +1,7 @@
 package com.avaje.ebean.config.dbplatform;
 
 import com.avaje.ebean.BackgroundExecutor;
+import com.avaje.ebean.dbmigration.ddlgeneration.platform.H2Ddl;
 
 import javax.sql.DataSource;
 
@@ -13,9 +14,7 @@ public class H2Platform extends DatabasePlatform {
     super();
     this.name = "h2";
     this.dbEncrypt = new H2DbEncrypt();
-    // like ? escape'' not working in the latest version H2 so just using no
-    // escape clause for now noting that backslash is an escape char for like in H2
-    this.likeClause = "like ?";
+    this.platformDdl = new H2Ddl(this.dbTypeMap, dbIdentity);
 
     // only support getGeneratedKeys with non-batch JDBC
     // so generally use SEQUENCE instead of IDENTITY for H2
@@ -24,16 +23,12 @@ public class H2Platform extends DatabasePlatform {
     this.dbIdentity.setSupportsSequence(true);
     this.dbIdentity.setSupportsIdentity(true);
 
-    this.openQuote = "\"";
-    this.closeQuote = "\"";
+    // like ? escape'' not working in the latest version H2 so just using no
+    // escape clause for now noting that backslash is an escape char for like in H2
+    this.likeClause = "like ?";
 
     // H2 data types match default JDBC types
     // so no changes to dbTypeMap required
-
-    this.dbDdlSyntax.setDropIfExists("if exists");
-    this.dbDdlSyntax.setDisableReferentialIntegrity("SET REFERENTIAL_INTEGRITY FALSE");
-    this.dbDdlSyntax.setEnableReferentialIntegrity("SET REFERENTIAL_INTEGRITY TRUE");
-    this.dbDdlSyntax.setForeignKeySuffix("on delete restrict on update restrict");
   }
 
   /**

src/main/java/com/avaje/ebean/config/dbplatform/HsqldbPlatform.java

@@ -1,6 +1,7 @@
 package com.avaje.ebean.config.dbplatform;
 
 import com.avaje.ebean.BackgroundExecutor;
+import com.avaje.ebean.dbmigration.ddlgeneration.platform.HsqldbDdl;
 
 import javax.sql.DataSource;
 import java.sql.Types;
@@ -14,32 +15,18 @@ public class HsqldbPlatform extends DatabasePlatform {
     super();
     this.name = "hsqldb";
     this.dbEncrypt = new H2DbEncrypt();
+    this.platformDdl = new HsqldbDdl(dbTypeMap, dbIdentity);
+
     this.dbIdentity.setIdType(IdType.IDENTITY);
     this.dbIdentity.setSupportsGetGeneratedKeys(true);
     this.dbIdentity.setSupportsSequence(true);
     this.dbIdentity.setSupportsIdentity(true);
 
-    this.openQuote = "\"";
-    this.closeQuote = "\"";
-
-    // H2 data types match default JDBC types
-    // so no changes to dbTypeMap required
     dbTypeMap.put(Types.INTEGER, new DbType("integer", false));
-
-    this.dbDdlSyntax.setDropIfExists("if exists");
-    this.dbDdlSyntax.setDisableReferentialIntegrity("SET DATABASE REFERENTIAL INTEGRITY FALSE");
-    this.dbDdlSyntax.setEnableReferentialIntegrity("SET DATABASE REFERENTIAL INTEGRITY TRUE");
-    this.dbDdlSyntax.setForeignKeySuffix("on delete restrict on update restrict");
-    this.dbDdlSyntax.setIdentity("GENERATED BY DEFAULT AS IDENTITY (START WITH 1) ");
   }
 
-  /**
-   * Return a H2 specific sequence IdGenerator that supports batch fetching
-   * sequence values.
-   */
   @Override
-  public IdGenerator createSequenceIdGenerator(BackgroundExecutor be,
-      DataSource ds, String seqName, int batchSize) {
+  public IdGenerator createSequenceIdGenerator(BackgroundExecutor be, DataSource ds, String seqName, int batchSize) {
 
     return new H2SequenceIdGenerator(be, ds, seqName, batchSize);
   }

src/main/java/com/avaje/ebean/config/dbplatform/IdGenerator.java

@@ -16,7 +16,7 @@ public interface IdGenerator {
   /**
    * The name of the default UUID generator.
    */
-  static final String AUTO_UUID = "auto.uuid";
+  String AUTO_UUID = "auto.uuid";
 
   /**
    * Return the name of the IdGenerator. For sequences this is the sequence

src/main/java/com/avaje/ebean/config/dbplatform/IdType.java

@@ -26,6 +26,15 @@ public enum IdType {
    * id properties of type UUID.
    * </p>
    */
-  GENERATOR;
+  GENERATOR,
+
+  /**
+   * Expected that the identity is externally set (for example a ISO code for
+   * country or currency or a user defined code for lookup tables).
+   * <p>
+   * Used when the key is a compound key or lookup table code.
+   * </p>
+   */
+  EXTERNAL
 
 }

src/main/java/com/avaje/ebean/config/dbplatform/MsSqlServer2005Platform.java

@@ -1,5 +1,7 @@
 package com.avaje.ebean.config.dbplatform;
 
+import com.avaje.ebean.dbmigration.ddlgeneration.platform.MsSqlServerDdl;
+
 import java.sql.Types;
 
 /**
@@ -21,8 +23,9 @@ public class MsSqlServer2005Platform extends DatabasePlatform {
     // due to lack of support for getGeneratedKeys in batch mode
     this.disallowBatchOnCascade = true;
     this.idInExpandedForm = true;
+    this.selectCountWithAlias = true;
     this.sqlLimiter = new MsSqlServer2005SqlLimiter();
-    this.dbDdlSyntax = new MsDdlSyntax();
+    this.platformDdl = new MsSqlServerDdl(dbTypeMap, dbIdentity);
     this.dbIdentity.setIdType(IdType.IDENTITY);
     this.dbIdentity.setSupportsGetGeneratedKeys(true);
     this.dbIdentity.setSupportsIdentity(true);
@@ -44,35 +47,9 @@ public class MsSqlServer2005Platform extends DatabasePlatform {
     dbTypeMap.put(Types.LONGVARBINARY, new DbType("image"));
     dbTypeMap.put(Types.LONGVARCHAR, new DbType("text"));
 
-    dbTypeMap.put(Types.DATE, new DbType("datetime"));
-    dbTypeMap.put(Types.TIME, new DbType("datetime"));
-    dbTypeMap.put(Types.TIMESTAMP, new DbType("datetime"));
-
-  }
-
-  /**
-   * MS SQL Server specific DDL Syntax.
-   */
-  public class MsDdlSyntax extends DbDdlSyntax {
-
-    MsDdlSyntax() {
-      this.identity = "identity(1,1)";
-      this.dropKeyConstraints = true;
-    }
-
-    /**
-     * Return some DDL to disable constraints on the given table.
-     */
-    public String dropKeyConstraintPrefix(String tableName, String fkName) {
-      return "IF OBJECT_ID('"+fkName+"', 'F') IS NOT NULL";
-    }
-
-    /**
-     * Return prefix text that goes before drop table.
-     */
-    public String dropTablePrefix(String tableName) {
-      return "IF OBJECT_ID('"+tableName+"', 'U') IS NOT NULL ";
-    }
+    dbTypeMap.put(Types.DATE, new DbType("date"));
+    dbTypeMap.put(Types.TIME, new DbType("time"));
+    dbTypeMap.put(Types.TIMESTAMP, new DbType("datetime2"));
 
   }
 

src/main/java/com/avaje/ebean/config/dbplatform/MsSqlServer2005SqlLimiter.java

@@ -31,10 +31,11 @@ public class MsSqlServer2005SqlLimiter implements SqlLimiter {
 
     if (firstRow < 1) {
       // just use top n
-      sb.append(" select top ").append(lastRow).append(" ");
+      sb.append(" select ");
       if (request.isDistinct()) {
         sb.append("distinct ");
       }
+      sb.append(" top ").append(lastRow).append(" ");
       sb.append(request.getDbSql());
       return new SqlLimitResponse(sb.toString(), false);
     }

src/main/java/com/avaje/ebean/config/dbplatform/MySqlHistorySupport.java

@@ -0,0 +1,9 @@
+package com.avaje.ebean.config.dbplatform;
+
+/**
+ * Runtime support for @History with MySql.
+ */
+public class MySqlHistorySupport extends DbViewHistorySupport {
+
+
+}

src/main/java/com/avaje/ebean/config/dbplatform/MySqlPlatform.java

@@ -1,6 +1,7 @@
 package com.avaje.ebean.config.dbplatform;
 
 import com.avaje.ebean.BackgroundExecutor;
+import com.avaje.ebean.dbmigration.ddlgeneration.platform.MySqlDdl;
 
 import javax.sql.DataSource;
 import java.sql.Types;
@@ -24,6 +25,8 @@ public class MySqlPlatform extends DatabasePlatform {
     this.likeClause = "like ? escape''";
     this.selectCountWithAlias = true;
     this.dbEncrypt = new MySqlDbEncrypt();
+    this.platformDdl = new MySqlDdl(this.dbTypeMap, this.dbIdentity);
+    this.historySupport = new MySqlHistorySupport();
 
     this.dbIdentity.setIdType(IdType.IDENTITY);
     this.dbIdentity.setSupportsGetGeneratedKeys(true);
@@ -43,12 +46,6 @@ public class MySqlPlatform extends DatabasePlatform {
     dbTypeMap.put(Types.BLOB, new MySqlBlob());
     dbTypeMap.put(Types.BINARY, new DbType("binary", 255));
     dbTypeMap.put(Types.VARBINARY, new DbType("varbinary", 255));
-
-    dbDdlSyntax.setMaxConstraintNameLength(64);
-    dbDdlSyntax.setDisableReferentialIntegrity("SET FOREIGN_KEY_CHECKS=0");
-    dbDdlSyntax.setEnableReferentialIntegrity("SET FOREIGN_KEY_CHECKS=1");
-    dbDdlSyntax.setForeignKeySuffix("on delete restrict on update restrict");
-
   }
 
   /**

src/main/java/com/avaje/ebean/config/dbplatform/Oracle9Platform.java

@@ -1,15 +0,0 @@
-package com.avaje.ebean.config.dbplatform;
-
-/**
- * Since Ebean v2.2.0 Oracle9 is no different from Oracle10.
- * <p>
- * This will be removed in the future.
- * </p>
- */
-public class Oracle9Platform extends Oracle10Platform {
-
-  public Oracle9Platform() {
-    super();
-  }
-
-}

src/main/java/com/avaje/ebean/config/dbplatform/OracleDbEncrypt.java

@@ -43,25 +43,25 @@ package com.avaje.ebean.config.dbplatform;
  * 
  * @author rbygrave
  */
-public class Oracle10DbEncrypt extends AbstractDbEncrypt {
+public class OracleDbEncrypt extends AbstractDbEncrypt {
 
   /**
    * Constructs the Oracle10DbEncrypt with default encrypt and decrypt stored procedures.
    */
-  public Oracle10DbEncrypt() {
+  public OracleDbEncrypt() {
     this("eb_encrypt", "eb_decrypt");
   }
 
   /**
    * Constructs the Oracle10DbEncrypt specifying encrypt and decrypt stored procedures.
    *
-   * @param encryptfunction the encrypt stored procedure
-   * @param decryptfunction the decrypt stored procedure
+   * @param encryptFunction the encrypt stored procedure
+   * @param decryptFunction the decrypt stored procedure
    */
-  public Oracle10DbEncrypt(String encryptfunction, String decryptfunction) {
+  public OracleDbEncrypt(String encryptFunction, String decryptFunction) {
 
-    this.varcharEncryptFunction = new OraVarcharFunction(encryptfunction, decryptfunction);
-    this.dateEncryptFunction = new OraDateFunction(encryptfunction, decryptfunction);
+    this.varcharEncryptFunction = new OraVarcharFunction(encryptFunction, decryptFunction);
+    this.dateEncryptFunction = new OraDateFunction(encryptFunction, decryptFunction);
   }
 
   /**

src/main/java/com/avaje/ebean/config/dbplatform/OracleDbHistorySupport.java

@@ -0,0 +1,37 @@
+package com.avaje.ebean.config.dbplatform;
+
+/**
+ * Oracle Total recall based history support.
+ */
+public class OracleDbHistorySupport extends DbStandardHistorySupport {
+
+  /**
+   * Return the ' as of timestamp ?' clause appended after the table name.
+   */
+  @Override
+  public String getAsOfViewSuffix(String asOfViewSuffix) {
+    return " as of TIMESTAMP ?";
+  }
+
+  @Override
+  public String getVersionsBetweenSuffix(String asOfViewSuffix) {
+    return " versions between timestamp ? and ?";
+  }
+
+  /**
+   * Returns the Oracle specific effective start column.
+   */
+  @Override
+  public String getSysPeriodLower(String tableAlias, String sysPeriod) {
+    return "versions_starttime";
+  }
+
+  /**
+   * Returns the Oracle specific effective end column.
+   */
+  @Override
+  public String getSysPeriodUpper(String tableAlias, String sysPeriod) {
+    return "versions_endtime";
+  }
+
+}

src/main/java/com/avaje/ebean/config/dbplatform/OraclePlatform.java

@@ -1,6 +1,7 @@
 package com.avaje.ebean.config.dbplatform;
 
 import com.avaje.ebean.BackgroundExecutor;
+import com.avaje.ebean.dbmigration.ddlgeneration.platform.Oracle10Ddl;
 
 import javax.sql.DataSource;
 import java.sql.Types;
@@ -8,15 +9,19 @@ import java.sql.Types;
 /**
  * Oracle10 and greater specific platform.
  */
-public class Oracle10Platform extends DatabasePlatform {
+public class OraclePlatform extends DatabasePlatform {
 
-  public Oracle10Platform() {
+  public OraclePlatform() {
     super();
     this.name = "oracle";
+    this.maxTableNameLength = 30;
+    this.maxConstraintNameLength = 30;
     // OnQueryOnly.CLOSE as a performance optimisation on Oracle
     this.onQueryOnly = OnQueryOnly.CLOSE;
-    this.dbEncrypt = new Oracle10DbEncrypt();
+    this.dbEncrypt = new OracleDbEncrypt();
     this.sqlLimiter = new RownumSqlLimiter();
+    this.platformDdl = new Oracle10Ddl(this.dbTypeMap, this.dbIdentity);
+    this.historySupport = new OracleDbHistorySupport();
 
     // Not using getGeneratedKeys as instead we will
     // batch load sequences which enables JDBC batch execution
@@ -48,15 +53,10 @@ public class Oracle10Platform extends DatabasePlatform {
     dbTypeMap.put(Types.BINARY, new DbType("raw", 255));
 
     dbTypeMap.put(Types.TIME, new DbType("timestamp"));
-
-    dbDdlSyntax.setDropTableCascade("cascade constraints purge");
-    dbDdlSyntax.setIdentity(null);
-    dbDdlSyntax.setMaxConstraintNameLength(30);
   }
 
   @Override
-  public IdGenerator createSequenceIdGenerator(BackgroundExecutor be, DataSource ds,
-      String seqName, int batchSize) {
+  public IdGenerator createSequenceIdGenerator(BackgroundExecutor be, DataSource ds, String seqName, int batchSize) {
 
     return new OracleSequenceIdGenerator(be, ds, seqName, batchSize);
   }

src/main/java/com/avaje/ebean/config/dbplatform/Postgres8Platform.java

@@ -1,67 +1,20 @@
 package com.avaje.ebean.config.dbplatform;
 
-import com.avaje.ebean.BackgroundExecutor;
-
-import javax.sql.DataSource;
-import java.sql.Types;
-
 /**
  * Postgres v8.3 specific platform.
  * <p>
  * No support for getGeneratedKeys.
  * </p>
  */
-public class Postgres8Platform extends DatabasePlatform {
+public class Postgres8Platform extends PostgresPlatform {
 
   public Postgres8Platform() {
     super();
-    this.name = "postgres";
-    this.selectCountWithAlias = true;
-    this.blobDbType = Types.LONGVARBINARY;
-    this.clobDbType = Types.VARCHAR;
-
-    this.dbEncrypt = new PostgresDbEncrypt();
-
     this.dbIdentity.setSupportsGetGeneratedKeys(false);
     this.dbIdentity.setIdType(IdType.SEQUENCE);
     this.dbIdentity.setSupportsSequence(true);
-
+    this.dbIdentity.setSupportsIdentity(true);
     this.columnAliasPrefix = "as c";
-    this.openQuote = "\"";
-    this.closeQuote = "\"";
-
-    // dbTypeMap.put(Types.BOOLEAN, new DbType("bit default 0"));
-
-    dbTypeMap.put(Types.INTEGER, new DbType("integer", false));
-    dbTypeMap.put(Types.DOUBLE, new DbType("float"));
-    dbTypeMap.put(Types.TINYINT, new DbType("smallint"));
-    dbTypeMap.put(Types.DECIMAL, new DbType("decimal", 38));
-
-    dbTypeMap.put(Types.BINARY, new DbType("bytea", false));
-    dbTypeMap.put(Types.VARBINARY, new DbType("bytea", false));
-
-    dbTypeMap.put(Types.BLOB, new DbType("bytea", false));
-    dbTypeMap.put(Types.CLOB, new DbType("text"));
-    dbTypeMap.put(Types.LONGVARBINARY, new DbType("bytea", false));
-    dbTypeMap.put(Types.LONGVARCHAR, new DbType("text"));
-
-    dbDdlSyntax.setDropTableCascade("cascade");
-    dbDdlSyntax.setDropIfExists("if exists");
-
   }
 
-  /**
-   * Create a Postgres specific sequence IdGenerator.
-   */
-  @Override
-  public IdGenerator createSequenceIdGenerator(BackgroundExecutor be, DataSource ds,
-      String seqName, int batchSize) {
-
-    return new PostgresSequenceIdGenerator(be, ds, seqName, batchSize);
-  }
-
-  @Override
-  protected String withForUpdate(String sql) {
-    return sql + " for update";
-  }
 }

src/main/java/com/avaje/ebean/config/dbplatform/PostgresDdlSyntax.java

@@ -1,25 +0,0 @@
-package com.avaje.ebean.config.dbplatform;
-
-public class PostgresDdlSyntax extends DbDdlSyntax {
-
-  /**
-   * Map bigint, integer and smallint into their equivilent serial types. 
-   */
-  @Override
-  public String getIdentityColumnDefn(String columnDefn) {
-    
-    //smallserial, serial and bigserial
-    if ("bigint".equalsIgnoreCase(columnDefn)) {
-      return "bigserial";
-    }
-    if ("integer".equalsIgnoreCase(columnDefn)) {
-      return "serial";
-    }
-    if ("smallint".equalsIgnoreCase(columnDefn)) {
-      return "smallserial";
-    }
-    
-    return columnDefn;
-  }
-
-}

src/main/java/com/avaje/ebean/config/dbplatform/PostgresHistorySupport.java

@@ -0,0 +1,39 @@
+package com.avaje.ebean.config.dbplatform;
+
+/**
+ * Postgres support for history features.
+ */
+public class PostgresHistorySupport extends DbViewHistorySupport {
+
+  /**
+   * Return 1 as we are using the postgres range type and hence don't need 2 bind variables.
+   */
+  @Override
+  public int getBindCount() {
+    return 1;
+  }
+
+  /**
+   * Build and return the 'as of' predicate for a given table alias.
+   * <p>
+   * Each @History entity involved in the query has this predicate added using the related table alias.
+   * </p>
+   */
+  @Override
+  public String getAsOfPredicate(String asOfTableAlias, String asOfSysPeriod) {
+
+    // for Postgres we are using the 'timestamp with timezone range' data type
+    // as our sys_period column so hence the predicate below
+    return asOfTableAlias + "." + asOfSysPeriod + " @> ?::timestamptz";
+  }
+
+  @Override
+  public String getSysPeriodLower(String tableAlias, String sysPeriod) {
+    return "lower(" + tableAlias + "." + sysPeriod + ")";
+  }
+
+  @Override
+  public String getSysPeriodUpper(String tableAlias, String sysPeriod) {
+    return "upper(" + tableAlias + "." + sysPeriod + ")";
+  }
+}

src/main/java/com/avaje/ebean/config/dbplatform/PostgresPlatform.java

@@ -1,6 +1,9 @@
 package com.avaje.ebean.config.dbplatform;
 
 import com.avaje.ebean.BackgroundExecutor;
+import com.avaje.ebean.config.ServerConfig;
+import com.avaje.ebean.dbmigration.ddlgeneration.DdlHandler;
+import com.avaje.ebean.dbmigration.ddlgeneration.platform.PostgresDdl;
 
 import javax.sql.DataSource;
 import java.sql.Types;
@@ -16,28 +19,32 @@ public class PostgresPlatform extends DatabasePlatform {
   public PostgresPlatform() {
     super();
     this.name = "postgres";
+
     // OnQueryOnly.CLOSE as a performance optimisation on Postgres
     this.onQueryOnly = OnQueryOnly.CLOSE;
     this.likeClause = "like ? escape''";
-    
-    this.dbDdlSyntax = new PostgresDdlSyntax();
-    
+
     this.selectCountWithAlias = true;
     this.blobDbType = Types.LONGVARBINARY;
     this.clobDbType = Types.VARCHAR;
 
     this.dbEncrypt = new PostgresDbEncrypt();
+    this.historySupport = new PostgresHistorySupport();
+    this.platformDdl = new PostgresDdl(this.dbTypeMap, this.dbIdentity);
 
     // Use Identity and getGeneratedKeys
     this.dbIdentity.setIdType(IdType.IDENTITY);
     this.dbIdentity.setSupportsGetGeneratedKeys(true);
     this.dbIdentity.setSupportsSequence(true);
 
-    this.columnAliasPrefix = "as c";
+    //this.columnAliasPrefix = "as c";
 
     this.openQuote = "\"";
     this.closeQuote = "\"";
 
+    DbType dbTypeText = new DbType("text");
+    DbType dbBytea = new DbType("bytea", false);
+
     dbTypeMap.put(DbType.HSTORE, new DbType("hstore"));
     dbTypeMap.put(DbType.JSON, new DbType("json"));
     dbTypeMap.put(DbType.JSONB, new DbType("jsonb"));
@@ -47,25 +54,28 @@ public class PostgresPlatform extends DatabasePlatform {
     dbTypeMap.put(Types.TINYINT, new DbType("smallint"));
     dbTypeMap.put(Types.DECIMAL, new DbType("decimal", 38));
 
-    dbTypeMap.put(Types.BINARY, new DbType("bytea", false));
-    dbTypeMap.put(Types.VARBINARY, new DbType("bytea", false));
+    dbTypeMap.put(Types.BINARY, dbBytea);
+    dbTypeMap.put(Types.VARBINARY, dbBytea);
 
-    dbTypeMap.put(Types.BLOB, new DbType("bytea", false));
-    dbTypeMap.put(Types.CLOB, new DbType("text"));
-    dbTypeMap.put(Types.LONGVARBINARY, new DbType("bytea", false));
-    dbTypeMap.put(Types.LONGVARCHAR, new DbType("text"));
+    dbTypeMap.put(Types.BLOB, dbBytea);
+    dbTypeMap.put(Types.CLOB, dbTypeText);
+    dbTypeMap.put(Types.LONGVARBINARY, dbBytea);
+    dbTypeMap.put(Types.LONGVARCHAR, dbTypeText);
 
-    dbDdlSyntax.setDropTableCascade("cascade");
-    dbDdlSyntax.setDropIfExists("if exists");
+  }
 
+  /**
+   * Return a DdlHandler instance for generating DDL for the specific platform.
+   */
+  public DdlHandler createDdlHandler(ServerConfig serverConfig) {
+    return this.platformDdl.createDdlHandler(serverConfig);
   }
 
   /**
    * Create a Postgres specific sequence IdGenerator.
    */
   @Override
-  public IdGenerator createSequenceIdGenerator(BackgroundExecutor be, DataSource ds,
-      String seqName, int batchSize) {
+  public IdGenerator createSequenceIdGenerator(BackgroundExecutor be, DataSource ds, String seqName, int batchSize) {
 
     return new PostgresSequenceIdGenerator(be, ds, seqName, batchSize);
   }

src/main/java/com/avaje/ebean/config/dbplatform/SQLitePlatform.java

@@ -1,22 +1,20 @@
 package com.avaje.ebean.config.dbplatform;
 
+import com.avaje.ebean.dbmigration.ddlgeneration.platform.SQLiteDdl;
+
 import java.sql.Types;
 
-import javax.sql.DataSource;
-
-import com.avaje.ebean.BackgroundExecutor;
-
 public class SQLitePlatform extends DatabasePlatform {
 
   public SQLitePlatform() {
     super();
     this.name = "sqlite";
+    this.platformDdl = new SQLiteDdl(dbTypeMap, dbIdentity);
 
     this.dbIdentity.setIdType(IdType.IDENTITY);
     this.dbIdentity.setSupportsGetGeneratedKeys(false);
+    this.dbIdentity.setSupportsSequence(false);
     this.dbIdentity.setSelectLastInsertedIdTemplate("select last_insert_rowid()");
-    this.openQuote = "\"";
-    this.closeQuote = "\"";
 
     this.booleanDbType = Types.INTEGER;
 
@@ -24,25 +22,7 @@ public class SQLitePlatform extends DatabasePlatform {
     dbTypeMap.put(Types.BOOLEAN, new DbType("int default 0"));
     dbTypeMap.put(Types.BIGINT, new DbType("integer"));
     dbTypeMap.put(Types.SMALLINT, new DbType("integer"));
-    
-    dbDdlSyntax.setInlinePrimaryKeyConstraint(true);
-    
-    // AutoIncrement goes the primary key declaration
-    dbDdlSyntax.setIdentity("");
-    dbDdlSyntax.setIdentitySuffix("AUTOINCREMENT");
 
-    dbDdlSyntax.setDisableReferentialIntegrity("PRAGMA foreign_keys = OFF");
-    dbDdlSyntax.setEnableReferentialIntegrity("PRAGMA foreign_keys = ON");
-  }
-
-  /**
-   * Return null in case there is a sequence annotation.
-   */
-  @Override
-  public IdGenerator createSequenceIdGenerator(BackgroundExecutor be,
-      DataSource ds, String seqName, int batchSize) {
-
-    return null;
   }
 
 }

src/main/java/com/avaje/ebean/config/dbplatform/SequenceIdGenerator.java

@@ -42,7 +42,7 @@ public abstract class SequenceIdGenerator implements IdGenerator {
 
   protected final ArrayList<Long> idList = new ArrayList<Long>(50);
 
-  protected int batchSize;
+  protected final int batchSize;
 
   protected int currentlyBackgroundLoading;
 

src/main/java/com/avaje/ebean/config/dbplatform/SimpleSequenceIdGenerator.java

@@ -61,8 +61,7 @@ public class SimpleSequenceIdGenerator implements IdGenerator {
       pstmt = c.prepareStatement(sql);
       rset = pstmt.executeQuery();
       if (rset.next()) {
-        int val = rset.getInt(1);
-        return Integer.valueOf(val);
+        return rset.getInt(1);
       } else {
         String m = "Always expecting 1 row from " + sql;
         throw new PersistenceException(m);

src/main/java/com/avaje/ebean/config/dbplatform/SqlAnywherePlatform.java

@@ -11,7 +11,6 @@ import java.sql.Types;
  * </ul>
  * </p>
  */
-
 public class SqlAnywherePlatform extends DatabasePlatform {
 
   public SqlAnywherePlatform() {

src/main/java/com/avaje/ebean/config/dbplatform/SqlLimiter.java

@@ -11,12 +11,7 @@ public interface SqlLimiter {
    * Note that this is removed for logging sql to the transaction log.
    * </p>
    */
-  static final char NEW_LINE = '\n';
-
-  /**
-   * The carriage return character.
-   */
-  static final char CARRIAGE_RETURN = '\r';
+  char NEW_LINE = '\n';
 
   /**
    * Add the SQL limiting statements around the query.

src/main/java/com/avaje/ebean/dbmigration/DbMigration.java

@@ -0,0 +1,327 @@
+package com.avaje.ebean.dbmigration;
+
+import com.avaje.ebean.Ebean;
+import com.avaje.ebean.EbeanServer;
+import com.avaje.ebean.config.DbConstraintNaming;
+import com.avaje.ebean.config.DbMigrationConfig;
+import com.avaje.ebean.config.ServerConfig;
+import com.avaje.ebean.config.dbplatform.DB2Platform;
+import com.avaje.ebean.config.dbplatform.DatabasePlatform;
+import com.avaje.ebean.config.dbplatform.DbPlatformName;
+import com.avaje.ebean.config.dbplatform.H2Platform;
+import com.avaje.ebean.config.dbplatform.MsSqlServer2005Platform;
+import com.avaje.ebean.config.dbplatform.MySqlPlatform;
+import com.avaje.ebean.config.dbplatform.OraclePlatform;
+import com.avaje.ebean.config.dbplatform.PostgresPlatform;
+import com.avaje.ebean.config.dbplatform.SQLitePlatform;
+import com.avaje.ebean.dbmigration.ddlgeneration.DdlWrite;
+import com.avaje.ebean.dbmigration.migration.Migration;
+import com.avaje.ebean.dbmigration.migrationreader.MigrationXmlWriter;
+import com.avaje.ebean.dbmigration.model.CurrentModel;
+import com.avaje.ebean.dbmigration.model.MConfiguration;
+import com.avaje.ebean.dbmigration.model.MigrationModel;
+import com.avaje.ebean.dbmigration.model.ModelContainer;
+import com.avaje.ebean.dbmigration.model.PlatformDdlWriter;
+import com.avaje.ebean.dbmigration.model.ModelDiff;
+import com.avaje.ebeaninternal.api.SpiEbeanServer;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.File;
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Generates DB Migration xml and sql scripts.
+ * <p>
+ * Reads the prior migrations and compares with the current model of the EbeanServer
+ * and generates a migration 'diff' in the form of xml document with the logical schema
+ * changes and a series of sql scripts to apply, rollback the applied changes if necessary
+ * and drop objects (drop tables, drop columns).
+ * </p>
+ * <p>
+ *   This does not run the migration or ddl scripts but just generates them.
+ * </p>
+ * <pre>{@code
+ *
+ *       DbMigration migration = new DbMigration();
+ *       migration.setPathToResources("src/main/resources");
+ *       migration.setPlatform(DbPlatformName.ORACLE);
+ *
+ *       migration.generateMigration();
+ *
+ * }</pre>
+ */
+public class DbMigration {
+
+  protected static final Logger logger = LoggerFactory.getLogger(DbMigration.class);
+
+  protected SpiEbeanServer server;
+
+  protected DbMigrationConfig migrationConfig;
+
+  protected String pathToResources = "src/main/resources";
+
+  protected DatabasePlatform databasePlatform;
+
+  protected List<Pair> platforms = new ArrayList<Pair>();
+
+  protected ServerConfig serverConfig;
+
+  protected DbConstraintNaming constraintNaming;
+
+  public DbMigration() {
+  }
+
+  /**
+   * Set the path from the current working directory to the application resources.
+   *
+   * This defaults to maven style 'src/main/resources'.
+   */
+  public void setPathToResources(String pathToResources) {
+    this.pathToResources = pathToResources;
+  }
+
+  /**
+   * Set the server to use to determine the current model.
+   * Typically this is not called explicitly.
+   */
+  public void setServer(EbeanServer ebeanServer) {
+    this.server = (SpiEbeanServer) ebeanServer;
+    setServerConfig(server.getServerConfig());
+  }
+
+  /**
+   * Set the serverConfig to use. Typically this is not called explicitly.
+   */
+  public void setServerConfig(ServerConfig config) {
+    if (this.serverConfig == null) {
+      this.serverConfig = config;
+    }
+    if (migrationConfig == null) {
+      this.migrationConfig = serverConfig.getMigrationConfig();
+    }
+    if (constraintNaming == null) {
+      this.constraintNaming = serverConfig.getConstraintNaming();
+    }
+  }
+
+  /**
+   * Set the specific platform to generate DDL for.
+   * <p>
+   * If not set this defaults to the platform of the default server.
+   * </p>
+   */
+  public void setPlatform(DbPlatformName platform) {
+    setPlatform(getPlatform(platform));
+  }
+
+  /**
+   * Set the specific platform to generate DDL for.
+   * <p>
+   * If not set this defaults to the platform of the default server.
+   * </p>
+   */
+  public void setPlatform(DatabasePlatform databasePlatform) {
+    this.databasePlatform = databasePlatform;
+    DbOffline.setPlatform(databasePlatform.getName());
+  }
+
+  /**
+   * Add an additional platform to write the migration DDL.
+   * <p>
+   * Use this when you want to generate sql scripts for multiple database platforms
+   * from the migration (e.g. generate migration sql for MySql, Postgres and Oracle).
+   * </p>
+   */
+  public void addPlatform(DbPlatformName platform, String prefix) {
+    if (!prefix.endsWith("-")) {
+      prefix += "-";
+    }
+    platforms.add(new Pair(getPlatform(platform), prefix));
+  }
+
+  /**
+   * Generate the next migration xml file and associated apply and rollback sql scripts.
+   * <p>
+   *   This does not run the migration or ddl scripts but just generates them.
+   * </p>
+   * <h3>Example: Run for a single specific platform</h3>
+   * <pre>{@code
+   *
+   *       DbMigration migration = new DbMigration();
+   *       migration.setPathToResources("src/main/resources");
+   *       migration.setPlatform(DbPlatformName.ORACLE);
+   *
+   *       migration.generateMigration();
+   *
+   * }</pre>
+   *
+   * <h3>Example: Run migration generating DDL for multiple platforms</h3>
+   * <pre>{@code
+   *
+   *       DbMigration migration = new DbMigration();
+   *       migration.setPathToResources("src/main/resources");
+   *
+   *       migration.addPlatform(DbPlatformName.POSTGRES, "pg");
+   *       migration.addPlatform(DbPlatformName.MYSQL, "mysql");
+   *       migration.addPlatform(DbPlatformName.ORACLE, "mysql");
+   *
+   *       migration.generateMigration();
+   *
+   * }</pre>
+   */
+  public void generateMigration() throws IOException {
+
+    // use this flag to stop other plugins like full DDL generation
+    DbOffline.setRunningMigration();
+
+    setDefaults();
+
+    try {
+      MigrationModel migrationModel = new MigrationModel(migrationConfig.getResourcePath());
+      ModelContainer migrated = migrationModel.read();
+      int nextMajorVersion = migrationModel.getNextMajorVersion();
+
+      logger.info("next migration version {}", nextMajorVersion);
+
+      CurrentModel currentModel = new CurrentModel(server, constraintNaming);
+      ModelContainer current = currentModel.read();
+
+      ModelDiff diff = new ModelDiff(migrated);
+      diff.compareTo(current);
+
+      if (diff.isEmpty()) {
+        logger.info("no changes detected - no migration written");
+        return;
+      }
+
+      // there were actually changes to write
+      Migration dbMigration = diff.getMigration();
+
+      File writePath = getWritePath();
+      logger.info("migration writing version {} to {}", nextMajorVersion, writePath.getAbsolutePath());
+      writeMigrationXml(dbMigration, writePath, nextMajorVersion);
+
+      if (databasePlatform != null) {
+        // writer needs the current model to provide table/column details for
+        // history ddl generation (triggers, history tables etc)
+        DdlWrite write = new DdlWrite(new MConfiguration(), currentModel.read());
+        PlatformDdlWriter writer = new PlatformDdlWriter(databasePlatform, serverConfig);
+        writer.processMigration(dbMigration, write, writePath, nextMajorVersion);
+      }
+
+      writeExtraPlatformDdl(nextMajorVersion, currentModel, dbMigration, writePath);
+
+    } finally {
+      DbOffline.reset();
+    }
+  }
+
+  /**
+   * Write any extra platform ddl.
+   */
+  protected void writeExtraPlatformDdl(int nextMajorVersion, CurrentModel currentModel, Migration dbMigration, File writePath) throws IOException {
+
+    for (Pair pair : platforms) {
+      DdlWrite platformBuffer = new DdlWrite(new MConfiguration(), currentModel.read());
+
+      PlatformDdlWriter platformWriter = new PlatformDdlWriter(pair.platform, serverConfig, pair.prefix);
+      platformWriter.processMigration(dbMigration, platformBuffer, writePath, nextMajorVersion);
+    }
+  }
+
+  /**
+   * Write the migration xml.
+   */
+  protected void writeMigrationXml(Migration dbMigration, File resourcePath, int migrationVersion) {
+
+    File file = new File(resourcePath, "v"+migrationVersion+".0.xml");
+    MigrationXmlWriter xmlWriter = new MigrationXmlWriter();
+    xmlWriter.write(dbMigration, file);
+  }
+
+  /**
+   * Set default server and platform if necessary.
+   */
+  protected void setDefaults() {
+    if (server == null) {
+      setServer(Ebean.getDefaultServer());
+    }
+    if (databasePlatform == null && platforms.isEmpty()) {
+      // not explicitly set not set a list of platforms so
+      // default to the platform of the default server
+      databasePlatform = server.getDatabasePlatform();
+      logger.debug("set platform to {}", databasePlatform.getName());
+    }
+  }
+
+  /**
+   * Return the file path to write the xml and sql to.
+   */
+  protected File getWritePath() {
+
+    // path to src/main/resources in typical maven project
+    File resourceRootDir = new File(pathToResources);
+
+    String resourcePath = migrationConfig.getResourcePath();
+
+    // expect to be a path to something like - src/main/resources/dbmigration/myapp
+    File path = new File(resourceRootDir, resourcePath);
+    if (!path.exists()) {
+      if (!path.mkdirs()) {
+        logger.debug("Unable to ensure migration directory exists at {}", path.getAbsolutePath());
+      }
+    }
+    return path;
+  }
+
+  /**
+   * Return the DatabasePlatform given the platform key.
+   */
+  protected DatabasePlatform getPlatform(DbPlatformName platform) {
+    switch (platform) {
+      case H2:
+        return new H2Platform();
+      case POSTGRES:
+        return new PostgresPlatform();
+      case MYSQL:
+        return new MySqlPlatform();
+      case ORACLE:
+        return new OraclePlatform();
+      case SQLSERVER:
+        return new MsSqlServer2005Platform();
+      case DB2:
+        return new DB2Platform();
+      case SQLITE:
+        return new SQLitePlatform();
+
+      default:
+        throw new IllegalArgumentException("Platform missing? " + platform);
+    }
+  }
+
+  /**
+   * Holds a platform and prefix. Used to generate multiple platform specific DDL
+   * for a single migration.
+   */
+  public static class Pair {
+
+    /**
+     * The platform to generate the DDL for.
+     */
+    public final DatabasePlatform platform;
+
+    /**
+     * A prefix included into the file/resource names indicating the platform.
+     */
+    public final String prefix;
+
+    public Pair(DatabasePlatform platform, String prefix) {
+      this.platform = platform;
+      this.prefix = prefix;
+    }
+  }
+
+}

src/main/java/com/avaje/ebean/dbmigration/DbOffline.java

@@ -0,0 +1,79 @@
+package com.avaje.ebean.dbmigration;
+
+import com.avaje.ebean.config.dbplatform.DbPlatformName;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * Helper to indicate that an EbeanServer should come up offline
+ * typically for DDL generation purposes.
+ */
+public class DbOffline {
+
+  private static final Logger logger = LoggerFactory.getLogger(DbOffline.class);
+
+  private static final String KEY = "ebean.dboffline";
+
+  private static boolean runningMigration;
+
+  /**
+   * Set the platform to use when creating the next EbeanServer instance.
+   */
+  public static void setPlatform(DbPlatformName dbPlatform) {
+    System.setProperty(KEY, dbPlatform.name());
+  }
+
+  /**
+   * Set the platform to use when creating the next EbeanServer instance.
+   */
+  public static void setPlatform(String platformName) {
+    System.setProperty(KEY, platformName);
+  }
+
+  /**
+   * Return the platform to use when creating the next EbeanServer instance.
+   */
+  public static String getPlatform() {
+    return System.getProperty(KEY);
+  }
+
+  /**
+   * Bring up the next EbeanServer instance using the H2 platform.
+   */
+  public static void asH2() {
+    setPlatform(DbPlatformName.H2);
+  }
+
+  /**
+   * Return true if the offline platform has been set.
+   */
+  public static boolean isSet() {
+    return getPlatform() != null;
+  }
+
+  /**
+   * Return true if the migration is running. This typically means don't run the
+   * plugins like full DDL generation.
+   */
+  public static boolean isRunningMigration() {
+    return runningMigration;
+  }
+
+  /**
+   * Called when the migration is running is order to stop other plugins
+   * like the full DDL generation from executing.
+   */
+  public static void setRunningMigration() {
+    runningMigration = true;
+  }
+
+  /**
+   * Reset the offline platform and runningMigration flag.
+   */
+  public static void reset() {
+    runningMigration = false;
+    System.clearProperty(KEY);
+    logger.debug("reset");
+  }
+
+}

src/main/java/com/avaje/ebean/dbmigration/DdlGenerator.java

@@ -1,5 +1,14 @@
-package com.avaje.ebeaninternal.server.ddl;
+package com.avaje.ebean.dbmigration;
 
+import com.avaje.ebean.Transaction;
+import com.avaje.ebean.config.ServerConfig;
+import com.avaje.ebean.dbmigration.model.CurrentModel;
+import com.avaje.ebeaninternal.api.SpiEbeanPlugin;
+import com.avaje.ebeaninternal.api.SpiEbeanServer;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import javax.persistence.PersistenceException;
 import java.io.BufferedReader;
 import java.io.File;
 import java.io.FileReader;
@@ -13,18 +22,6 @@ import java.sql.SQLException;
 import java.util.ArrayList;
 import java.util.List;
 
-import javax.persistence.PersistenceException;
-
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
-
-import com.avaje.ebean.Transaction;
-import com.avaje.ebean.config.NamingConvention;
-import com.avaje.ebean.config.ServerConfig;
-import com.avaje.ebean.config.dbplatform.DatabasePlatform;
-import com.avaje.ebeaninternal.api.SpiEbeanPlugin;
-import com.avaje.ebeaninternal.api.SpiEbeanServer;
-
 /**
  * Controls the generation of DDL and potentially runs the resulting scripts.
  */
@@ -34,24 +31,17 @@ public class DdlGenerator implements SpiEbeanPlugin {
 
   private SpiEbeanServer server;
 
-  private DatabasePlatform dbPlatform;
-
-  private int summaryLength = 80;
-
   private boolean generateDdl;
   private boolean runDdl;
 
+  private CurrentModel currentModel;
   private String dropContent;
   private String createContent;
 
-  private NamingConvention namingConvention;
-
-  public void setup(SpiEbeanServer server, DatabasePlatform dbPlatform, ServerConfig serverConfig) {
+  public void setup(SpiEbeanServer server, ServerConfig serverConfig) {
     this.server = server;
-    this.dbPlatform = dbPlatform;
     this.generateDdl = serverConfig.isDdlGenerate();
     this.runDdl = serverConfig.isDdlRun();
-    this.namingConvention = serverConfig.getNamingConvention();
   }
 
   /**
@@ -103,10 +93,8 @@ public class DdlGenerator implements SpiEbeanPlugin {
     try {
       String c = generateDropDdl();
       writeFile(dropFile, c);
-
     } catch (IOException e) {
-      String msg = "Error generating Drop DDL";
-      throw new PersistenceException(msg, e);
+      throw new PersistenceException("Error generating Drop DDL", e);
     }
   }
 
@@ -115,65 +103,44 @@ public class DdlGenerator implements SpiEbeanPlugin {
     try {
       String c = generateCreateDdl();
       writeFile(createFile, c);
-
     } catch (IOException e) {
-      String msg = "Error generating Create DDL";
-      throw new PersistenceException(msg, e);
+      throw new PersistenceException("Error generating Create DDL", e);
     }
   }
 
   public String generateDropDdl() {
 
-    DdlGenContext ctx = createContext();
-
-    if (ctx.getDdlSyntax().isDropKeyConstraints()) {
-      // generate drop foreign key constraint statements (sql server joy)
-      AddForeignKeysVisitor fkeys = new AddForeignKeysVisitor(false, ctx);
-      VisitorUtil.visit(server, fkeys);
-      ctx.writeNewLine();
+    try {
+      dropContent = currentModel().getDropDdl();
+      return dropContent;
+    } catch (IOException e) {
+      throw new RuntimeException(e);
     }
-
-    DropTableVisitor drop = new DropTableVisitor(ctx);
-    VisitorUtil.visit(server, drop);
-
-    DropSequenceVisitor dropSequence = new DropSequenceVisitor(ctx);
-    VisitorUtil.visit(server, dropSequence);
-
-    ctx.flush();
-    dropContent = ctx.getContent();
-    return dropContent;
   }
 
   public String generateCreateDdl() {
 
-    DdlGenContext ctx = createContext();
-    CreateTableVisitor create = new CreateTableVisitor(ctx);
-    VisitorUtil.visit(server, create);
-
-    CreateSequenceVisitor createSequence = new CreateSequenceVisitor(ctx);
-    VisitorUtil.visit(server, createSequence);
-
-    AddForeignKeysVisitor fkeys = new AddForeignKeysVisitor(true, ctx);
-    VisitorUtil.visit(server, fkeys);
-
-    CreateIndexVisitor indexes = new CreateIndexVisitor(ctx);
-    VisitorUtil.visit(server, indexes);
-
-    ctx.flush();
-    createContent = ctx.getContent();
-    return createContent;
+    try {
+      createContent = currentModel().getCreateDdl();
+      return createContent;
+    } catch (IOException e) {
+      throw new RuntimeException(e);
+    }
   }
 
   protected String getDropFileName() {
-    return server.getName() + "-drop.sql";
+    return server.getName() + "-drop-all.sql";
   }
 
   protected String getCreateFileName() {
-    return server.getName() + "-create.sql";
+    return server.getName() + "-create-all.sql";
   }
 
-  protected DdlGenContext createContext() {
-    return new DdlGenContext(dbPlatform, namingConvention);
+  protected CurrentModel currentModel() {
+    if (currentModel == null) {
+      currentModel = new CurrentModel(server);
+    }
+    return currentModel;
   }
 
   protected void writeFile(String fileName, String fileContent) throws IOException {
@@ -201,7 +168,7 @@ public class DdlGenerator implements SpiEbeanPlugin {
     FileReader fr = new FileReader(f);
     LineNumberReader lr = new LineNumberReader(fr);
     try {
-      String s = null;
+      String s;
       while ((s = lr.readLine()) != null) {
         buf.append(s).append("\n");
       }
@@ -233,8 +200,7 @@ public class DdlGenerator implements SpiEbeanPlugin {
       t.commit();
 
     } catch (Exception e) {
-      String msg = "Error: " + e.getMessage();
-      throw new PersistenceException(msg, e);
+      throw new PersistenceException("Error: " + e.getMessage(), e);
     } finally {
       t.end();
     }
@@ -274,7 +240,7 @@ public class DdlGenerator implements SpiEbeanPlugin {
         stmt = stmt.substring(0, stmt.length() - 1);
       }
 
-      logger.trace("executing " + oneOf + " " + getSummary(stmt));
+      logger.info("executing " + oneOf + " " + getSummary(stmt));
 
       pstmt = c.prepareStatement(stmt);
       pstmt.execute();
@@ -340,8 +306,8 @@ public class DdlGenerator implements SpiEbeanPlugin {
   }
 
   private String getSummary(String s) {
-    if (s.length() > summaryLength) {
-      return s.substring(0, summaryLength).trim() + "...";
+    if (s.length() > 80) {
+      return s.substring(0, 80).trim() + "...";
     }
     return s;
   }

src/main/java/com/avaje/ebean/dbmigration/ddlgeneration/BaseDdlHandler.java

@@ -0,0 +1,108 @@
+package com.avaje.ebean.dbmigration.ddlgeneration;
+
+import com.avaje.ebean.config.ServerConfig;
+import com.avaje.ebean.dbmigration.ddlgeneration.platform.BaseTableDdl;
+import com.avaje.ebean.dbmigration.ddlgeneration.platform.PlatformDdl;
+import com.avaje.ebean.dbmigration.migration.AddColumn;
+import com.avaje.ebean.dbmigration.migration.AddHistoryTable;
+import com.avaje.ebean.dbmigration.migration.AlterColumn;
+import com.avaje.ebean.dbmigration.migration.ChangeSet;
+import com.avaje.ebean.dbmigration.migration.CreateIndex;
+import com.avaje.ebean.dbmigration.migration.CreateTable;
+import com.avaje.ebean.dbmigration.migration.DropColumn;
+import com.avaje.ebean.dbmigration.migration.DropHistoryTable;
+import com.avaje.ebean.dbmigration.migration.DropIndex;
+import com.avaje.ebean.dbmigration.migration.DropTable;
+
+import java.io.IOException;
+import java.util.List;
+
+/**
+ *
+ */
+public class BaseDdlHandler implements DdlHandler {
+
+  protected final TableDdl tableDdl;
+
+  public BaseDdlHandler(ServerConfig serverConfig, PlatformDdl platformDdl) {
+    this.tableDdl = new BaseTableDdl(serverConfig, platformDdl);
+  }
+
+  @Override
+  public void generate(DdlWrite writer, ChangeSet changeSet) throws IOException {
+
+    List<Object> changeSetChildren = changeSet.getChangeSetChildren();
+    for (Object change : changeSetChildren) {
+      if (change instanceof CreateTable) {
+        generate(writer, (CreateTable) change);
+      } else if (change instanceof DropTable) {
+        generate(writer, (DropTable) change);
+      } else if (change instanceof CreateIndex) {
+        generate(writer, (CreateIndex) change);
+      } else if (change instanceof DropIndex) {
+        generate(writer, (DropIndex) change);
+      } else if (change instanceof AddColumn) {
+        generate(writer, (AddColumn) change);
+      } else if (change instanceof DropColumn) {
+        generate(writer, (DropColumn) change);
+      } else if (change instanceof AlterColumn) {
+        generate(writer, (AlterColumn) change);
+      } else if (change instanceof AddHistoryTable) {
+        generate(writer, (AddHistoryTable) change);
+      } else if (change instanceof DropHistoryTable) {
+        generate(writer, (DropHistoryTable) change);
+      }
+    }
+  }
+
+  @Override
+  public void generateExtra(DdlWrite write) throws IOException {
+    tableDdl.generateExtra(write);
+  }
+
+  @Override
+  public void generate(DdlWrite writer, CreateTable createTable) throws IOException {
+    tableDdl.generate(writer, createTable);
+  }
+
+  @Override
+  public void generate(DdlWrite writer, DropTable dropTable) throws IOException {
+    tableDdl.generate(writer, dropTable);
+  }
+
+  @Override
+  public void generate(DdlWrite writer, AddColumn addColumn) throws IOException {
+    tableDdl.generate(writer, addColumn);
+  }
+
+  @Override
+  public void generate(DdlWrite writer, DropColumn dropColumn) throws IOException {
+    tableDdl.generate(writer, dropColumn);
+  }
+
+  @Override
+  public void generate(DdlWrite writer, AlterColumn alterColumn) throws IOException {
+    tableDdl.generate(writer, alterColumn);
+  }
+
+  @Override
+  public void generate(DdlWrite writer, AddHistoryTable addHistoryTable) throws IOException {
+    tableDdl.generate(writer, addHistoryTable);
+  }
+
+  @Override
+  public void generate(DdlWrite writer, DropHistoryTable dropHistoryTable) throws IOException {
+    tableDdl.generate(writer, dropHistoryTable);
+  }
+
+  @Override
+  public void generate(DdlWrite writer, CreateIndex createIndex) throws IOException {
+    tableDdl.generate(writer, createIndex);
+  }
+
+  @Override
+  public void generate(DdlWrite writer, DropIndex dropIndex) throws IOException {
+    tableDdl.generate(writer, dropIndex);
+  }
+
+}

src/main/java/com/avaje/ebean/dbmigration/ddlgeneration/ColumnDdl.java

@@ -0,0 +1,28 @@
+package com.avaje.ebean.dbmigration.ddlgeneration;
+
+import com.avaje.ebean.dbmigration.migration.AddColumn;
+import com.avaje.ebean.dbmigration.migration.AlterColumn;
+import com.avaje.ebean.dbmigration.migration.DropColumn;
+
+import java.io.IOException;
+
+/**
+ * Write DDL for AddColumn , DropColumn or AlterColumn.
+ */
+public interface ColumnDdl {
+
+  /**
+   * Write the add column change.
+   */
+  void generate(DdlWrite writer, AddColumn addColumn) throws IOException;
+
+  /**
+   * Write the drop column change.
+   */
+  void generate(DdlWrite writer, DropColumn dropColumn) throws IOException;
+
+  /**
+   * Write the alter column changes.
+   */
+  void generate(DdlWrite writer, AlterColumn alterColumn) throws IOException;
+}

src/main/java/com/avaje/ebean/dbmigration/ddlgeneration/DdlBuffer.java

@@ -0,0 +1,57 @@
+package com.avaje.ebean.dbmigration.ddlgeneration;
+
+import com.avaje.ebean.dbmigration.model.MConfiguration;
+
+import java.io.IOException;
+
+/**
+ * Buffer to append generated DDL to.
+ */
+public interface DdlBuffer {
+
+  /**
+   * Return the configuration (default tablespaces etc).
+   */
+  MConfiguration getConfiguration();
+
+  /**
+   * Return true if the buffer is empty.
+   */
+  boolean isEmpty();
+
+  /**
+   * Append DDL content to the buffer.
+   */
+  DdlBuffer append(String content) throws IOException;
+
+  /**
+   * Append DDL content to the buffer with space padding.
+   */
+  DdlBuffer append(String type, int space) throws IOException;
+
+  /**
+   * Append a value that is potentially null or empty and proceed it with a space if so.
+   */
+  DdlBuffer appendWithSpace(String foreignKeyRestrict) throws IOException;
+
+  /**
+   * Append new line character to the buffer.
+   */
+  DdlBuffer newLine() throws IOException;
+
+  /**
+   * Append the end of statement content.
+   */
+  DdlBuffer endOfStatement() throws IOException;
+
+  /**
+   * End of a change - add some whitespace.
+   */
+  DdlBuffer end() throws IOException;
+
+  /**
+   * Return the buffer content.
+   */
+  String getBuffer();
+
+}

src/main/java/com/avaje/ebean/dbmigration/ddlgeneration/DdlHandler.java

@@ -0,0 +1,41 @@
+package com.avaje.ebean.dbmigration.ddlgeneration;
+
+import com.avaje.ebean.dbmigration.migration.AddColumn;
+import com.avaje.ebean.dbmigration.migration.AddHistoryTable;
+import com.avaje.ebean.dbmigration.migration.AlterColumn;
+import com.avaje.ebean.dbmigration.migration.ChangeSet;
+import com.avaje.ebean.dbmigration.migration.CreateIndex;
+import com.avaje.ebean.dbmigration.migration.CreateTable;
+import com.avaje.ebean.dbmigration.migration.DropColumn;
+import com.avaje.ebean.dbmigration.migration.DropHistoryTable;
+import com.avaje.ebean.dbmigration.migration.DropIndex;
+import com.avaje.ebean.dbmigration.migration.DropTable;
+
+import java.io.IOException;
+
+/**
+ */
+public interface DdlHandler {
+
+  void generate(DdlWrite writer, ChangeSet changeSet) throws IOException;
+
+  void generate(DdlWrite writer, CreateTable createTable) throws IOException;
+
+  void generate(DdlWrite writer, DropTable dropTable) throws IOException;
+
+  void generate(DdlWrite writer, AddColumn addColumn) throws IOException;
+
+  void generate(DdlWrite writer, DropColumn dropColumn) throws IOException;
+
+  void generate(DdlWrite writer, AlterColumn alterColumn) throws IOException;
+
+  void generate(DdlWrite writer, AddHistoryTable addHistoryTable) throws IOException;
+
+  void generate(DdlWrite writer, DropHistoryTable dropHistoryTable) throws IOException;
+
+  void generate(DdlWrite writer, CreateIndex createIndex) throws IOException;
+
+  void generate(DdlWrite writer, DropIndex dropIndex) throws IOException;
+
+  void generateExtra(DdlWrite write) throws IOException;
+}

src/main/java/com/avaje/ebean/dbmigration/ddlgeneration/DdlWrite.java

@@ -0,0 +1,160 @@
+package com.avaje.ebean.dbmigration.ddlgeneration;
+
+import com.avaje.ebean.dbmigration.ddlgeneration.platform.BaseDdlBuffer;
+import com.avaje.ebean.dbmigration.model.MConfiguration;
+import com.avaje.ebean.dbmigration.model.MTable;
+import com.avaje.ebean.dbmigration.model.ModelContainer;
+
+/**
+ * Write context holding the buffers for both apply and rollback DDL.
+ */
+public class DdlWrite {
+
+  private final ModelContainer currentModel;
+
+  private final DdlBuffer apply;
+
+  private final DdlBuffer applyForeignKeys;
+
+  private final DdlBuffer applyHistory;
+
+  private final DdlBuffer rollbackForeignKeys;
+
+  private final DdlBuffer rollback;
+
+  /**
+   * For DDL that drops tables and columns etc.
+   *
+   * This DDL typically can not run automatically in production as there is most commonly
+   * existing servers running the application using these tables and columns. Typically
+   * these drop statements may be executed AFTER all the servers in the application have
+   * migrated onto new code.
+   */
+  private final DdlBuffer drop;
+
+  /**
+   * For use when History is turned off for a base table or history is no longer
+   * desired on specific columns. This DDL should typically execute manually after review
+   * by DBA's.
+   */
+  private final DdlBuffer dropHistory;
+
+  /**
+   * Create without any configuration or current model (no history support).
+   */
+  public DdlWrite() {
+    this(new MConfiguration(), new ModelContainer());
+  }
+
+  /**
+   * Create with a configuration.
+   */
+  public DdlWrite(MConfiguration configuration, ModelContainer currentModel) {
+    this.currentModel = currentModel;
+    this.apply = new BaseDdlBuffer(configuration);
+    this.applyForeignKeys = new BaseDdlBuffer(configuration);
+    this.applyHistory = new BaseDdlBuffer(configuration);
+    this.rollbackForeignKeys = new BaseDdlBuffer(configuration);
+    this.rollback = new BaseDdlBuffer(configuration);
+    this.drop = new BaseDdlBuffer(configuration);
+    this.dropHistory = new BaseDdlBuffer(configuration);
+  }
+
+  /**
+   * Return the Table information from the current model.
+   * <p>
+   * This is typically required for the history support (used to determine the list of columns
+   * included in the history when creating or recreating the associated trigger/stored procedure).
+   * </p>
+   */
+  public MTable getTable(String tableName) {
+    return currentModel.getTable(tableName);
+  }
+
+  /**
+   * Return true if the apply buffers are all empty.
+   */
+  public boolean isApplyEmpty() {
+    return apply.getBuffer().isEmpty()
+        && applyForeignKeys.getBuffer().isEmpty()
+        && applyHistory.getBuffer().isEmpty();
+  }
+
+  /**
+   * Return true if the apply rollback buffers are all empty.
+   */
+  public boolean isApplyRollbackEmpty() {
+    return rollback.getBuffer().isEmpty()
+        && rollbackForeignKeys.getBuffer().isEmpty();
+  }
+
+  /**
+   * Return true the drop buffers are empty.
+   */
+  public boolean isDropEmpty() {
+    return drop.getBuffer().isEmpty() && dropHistory.getBuffer().isEmpty();
+  }
+
+  /**
+   * Return the buffer that APPLY DDL is written to.
+   */
+  public DdlBuffer apply() {
+    return apply;
+  }
+
+  /**
+   * Return the buffer that APPLY DDL is written to for foreign keys and their associated indexes.
+   * <p>
+   * Statements added to this buffer are executed after all the normal apply statements and
+   * typically 'add foreign key' is added to this buffer.
+   */
+  public DdlBuffer applyForeignKeys() {
+    return applyForeignKeys;
+  }
+
+  /**
+   * Return the buffer that apply history DDL is written to.
+   */
+  public DdlBuffer applyHistory() {
+    return applyHistory;
+  }
+
+  /**
+   * Return the buffer that ROLLBACK DDL is written to for foreign keys and associated indexes.
+   */
+  public DdlBuffer rollbackForeignKeys() {
+    return rollbackForeignKeys;
+  }
+
+  /**
+   * Return the buffer that ROLLBACK DDL is written to which is considered safe to run when
+   * apply changes fail to execute. This will reverse the apply changes typically dropping
+   * newly created tables, foreign keys etc.
+   * <p>
+   * When apply changes are made against DB's that support transactional DDL you could argue
+   * that these rollback statements are not necessary.
+   * <p>
+   * Note that statements added to this rollback buffer are executed after foreign key rollback
+   * has been executed.
+   */
+  public DdlBuffer rollback() {
+    return rollback;
+  }
+
+  /**
+   * Return the buffer that destructive changes are written to. This is typically drop table and
+   * drop column.
+   */
+  public DdlBuffer drop() {
+    return drop;
+  }
+
+  /**
+   * Return the buffer that is used when history is no longer required on a table or specific columns.
+   */
+  public DdlBuffer dropHistory() {
+    return dropHistory;
+  }
+
+
+}

src/main/java/com/avaje/ebean/dbmigration/ddlgeneration/TableDdl.java

@@ -0,0 +1,69 @@
+package com.avaje.ebean.dbmigration.ddlgeneration;
+
+import com.avaje.ebean.dbmigration.migration.AddColumn;
+import com.avaje.ebean.dbmigration.migration.AddHistoryTable;
+import com.avaje.ebean.dbmigration.migration.AlterColumn;
+import com.avaje.ebean.dbmigration.migration.CreateIndex;
+import com.avaje.ebean.dbmigration.migration.CreateTable;
+import com.avaje.ebean.dbmigration.migration.DropColumn;
+import com.avaje.ebean.dbmigration.migration.DropHistoryTable;
+import com.avaje.ebean.dbmigration.migration.DropIndex;
+import com.avaje.ebean.dbmigration.migration.DropTable;
+
+import java.io.IOException;
+
+/**
+ * Write table DDL.
+ */
+public interface TableDdl {
+
+  /**
+   * Generate the create table change.
+   */
+  void generate(DdlWrite writer, CreateTable createTable) throws IOException;
+
+  /**
+   * Write the drop column change.
+   */
+  void generate(DdlWrite writer, DropTable dropTable) throws IOException;
+
+  /**
+   * Write the add column change.
+   */
+  void generate(DdlWrite writer, AddColumn addColumn) throws IOException;
+
+  /**
+   * Write the alter column changes.
+   */
+  void generate(DdlWrite writer, AlterColumn alterColumn) throws IOException;
+
+  /**
+   * Write the drop column change.
+   */
+  void generate(DdlWrite writer, DropColumn dropColumn) throws IOException;
+
+  /**
+   * Write the AddHistoryTable change.
+   */
+  void generate(DdlWrite writer, AddHistoryTable addHistoryTable) throws IOException;
+
+  /**
+   * Write the DropHistoryTable change.
+   */
+  void generate(DdlWrite writer, DropHistoryTable dropHistoryTable) throws IOException;
+
+  /**
+   * Generate the create index change.
+   */
+  void generate(DdlWrite writer, CreateIndex createIndex) throws IOException;
+
+  /**
+   * Write the drop index change.
+   */
+  void generate(DdlWrite writer, DropIndex dropIndex) throws IOException;
+
+  /**
+   * Generate any extra DDL such as regeneration of history triggers.
+   */
+  void generateExtra(DdlWrite write) throws IOException;
+}

src/main/java/com/avaje/ebean/dbmigration/ddlgeneration/platform/BaseDdlBuffer.java

@@ -0,0 +1,88 @@
+package com.avaje.ebean.dbmigration.ddlgeneration.platform;
+
+import com.avaje.ebean.dbmigration.ddlgeneration.DdlBuffer;
+import com.avaje.ebean.dbmigration.model.MConfiguration;
+
+import java.io.IOException;
+import java.io.StringWriter;
+
+/**
+ * Base implementation of DdlBuffer using an underlying writer.
+ */
+public class BaseDdlBuffer implements DdlBuffer {
+
+  protected final StringWriter writer;
+
+  protected final MConfiguration configuration;
+
+  public BaseDdlBuffer(MConfiguration configuration) {
+    this.configuration = configuration;
+    this.writer = new StringWriter();
+  }
+
+  @Override
+  public MConfiguration getConfiguration() {
+    return configuration;
+  }
+
+  @Override
+  public boolean isEmpty() {
+    return writer.getBuffer().length() == 0;
+  }
+
+  @Override
+  public DdlBuffer appendWithSpace(String foreignKeyRestrict) throws IOException {
+    if (foreignKeyRestrict != null && !foreignKeyRestrict.isEmpty()) {
+      writer.append(" ").append(foreignKeyRestrict);
+    }
+    return this;
+  }
+
+  @Override
+  public DdlBuffer append(String content) throws IOException {
+    writer.append(content);
+    return this;
+  }
+
+  @Override
+  public DdlBuffer append(String content, int space) throws IOException {
+    writer.append(content);
+    appendSpace(space, content);
+    return this;
+  }
+
+  protected void appendSpace(int max, String content) throws IOException {
+    int space = max - content.length();
+    if (space > 0) {
+      for (int i = 0; i < space; i++) {
+        append(" ");
+      }
+    }
+  }
+
+  @Override
+  public DdlBuffer endOfStatement() throws IOException {
+    writer.append(";\n");
+    return this;
+  }
+
+  /**
+   * Used to demarcate the end of a series of statements.
+   * This should be just whitespace or a sql comment.
+   */
+  @Override
+  public DdlBuffer end() throws IOException {
+    writer.append("\n");
+    return this;
+  }
+
+  @Override
+  public DdlBuffer newLine() throws IOException {
+    writer.append("\n");
+    return this;
+  }
+
+  public String getBuffer() {
+    return writer.toString();
+  }
+}

src/main/java/com/avaje/ebean/dbmigration/ddlgeneration/platform/BaseTableDdl.java

@@ -0,0 +1,780 @@
+package com.avaje.ebean.dbmigration.ddlgeneration.platform;
+
+import com.avaje.ebean.config.DbConstraintNaming;
+import com.avaje.ebean.config.NamingConvention;
+import com.avaje.ebean.config.ServerConfig;
+import com.avaje.ebean.config.dbplatform.IdType;
+import com.avaje.ebean.dbmigration.ddlgeneration.DdlBuffer;
+import com.avaje.ebean.dbmigration.ddlgeneration.DdlWrite;
+import com.avaje.ebean.dbmigration.ddlgeneration.TableDdl;
+import com.avaje.ebean.dbmigration.ddlgeneration.platform.util.IndexSet;
+import com.avaje.ebean.dbmigration.migration.AddColumn;
+import com.avaje.ebean.dbmigration.migration.AddHistoryTable;
+import com.avaje.ebean.dbmigration.migration.AlterColumn;
+import com.avaje.ebean.dbmigration.migration.Column;
+import com.avaje.ebean.dbmigration.migration.CreateIndex;
+import com.avaje.ebean.dbmigration.migration.CreateTable;
+import com.avaje.ebean.dbmigration.migration.DropColumn;
+import com.avaje.ebean.dbmigration.migration.DropHistoryTable;
+import com.avaje.ebean.dbmigration.migration.DropIndex;
+import com.avaje.ebean.dbmigration.migration.DropTable;
+import com.avaje.ebean.dbmigration.migration.ForeignKey;
+import com.avaje.ebean.dbmigration.migration.UniqueConstraint;
+import com.avaje.ebean.dbmigration.model.MTable;
+
+import java.io.IOException;
+import java.math.BigInteger;
+import java.util.ArrayList;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+
+/**
+ * Base implementation for 'create table' and 'alter table' statements.
+ */
+public class BaseTableDdl implements TableDdl {
+
+  protected final DbConstraintNaming naming;
+
+  protected final NamingConvention namingConvention;
+
+  protected final PlatformDdl platformDdl;
+
+  protected final String historyTableSuffix;
+
+  /**
+   * Used to check that indexes on foreign keys should be skipped as a unique index on the columns
+   * already exists.
+   */
+  protected IndexSet indexSet = new IndexSet();
+
+  /**
+   * Used when unique constraints specifically for OneToOne can't be created normally (MsSqlServer).
+   */
+  protected List<Column> externalUnique = new ArrayList<Column>();
+
+  // counters used when constraint names are truncated due to maximum length
+  // and these counters are used to keep the constraint name unique
+  protected int countCheck;
+  protected int countUnique;
+  protected int countForeignKey;
+  protected int countIndex;
+
+  /**
+   * Base tables that have associated history tables that need their triggers/functions regenerated as
+   * columns have been added, removed, included or excluded.
+   */
+  protected Map<String, HistoryTableUpdate> regenerateHistoryTriggers = new LinkedHashMap<String, HistoryTableUpdate>();
+
+  /**
+   * Construct with a naming convention and platform specific DDL.
+   */
+  public BaseTableDdl(ServerConfig serverConfig, PlatformDdl platformDdl) {
+    this.namingConvention = serverConfig.getNamingConvention();
+    this.naming = serverConfig.getConstraintNaming();
+    this.historyTableSuffix = serverConfig.getHistoryTableSuffix();
+    this.platformDdl = platformDdl;
+    this.platformDdl.configure(serverConfig);
+  }
+
+  /**
+   * Reset counters and index set for each table processed.
+   */
+  protected void reset() {
+    indexSet.clear();
+    externalUnique.clear();
+    countCheck = 0;
+    countUnique = 0;
+    countForeignKey = 0;
+    countIndex = 0;
+  }
+
+  /**
+   * Generate the appropriate 'create table' and matching 'drop table' statements
+   * and add them to the appropriate 'apply' and 'rollback' buffers.
+   */
+  @Override
+  public void generate(DdlWrite writer, CreateTable createTable) throws IOException {
+
+    reset();
+
+    String tableName = lowerName(createTable.getName());
+    List<Column> columns = createTable.getColumn();
+    List<Column> pk = determinePrimaryKeyColumns(columns);
+
+    boolean singleColumnPrimaryKey = (pk.size() == 1);
+    boolean useIdentity = false;
+    boolean useSequence = false;
+
+    if (singleColumnPrimaryKey) {
+      IdType useDbIdentityType = platformDdl.useIdentityType(createTable.getIdentityType());
+      useIdentity = (IdType.IDENTITY == useDbIdentityType);
+      useSequence = (IdType.SEQUENCE == useDbIdentityType);
+    }
+
+    DdlBuffer apply = writer.apply();
+    apply.append("create table ").append(tableName).append(" (");
+    writeTableColumns(apply, columns, useIdentity);
+    writeCheckConstraints(apply, createTable);
+    writeUniqueConstraints(apply, createTable);
+    writeCompoundUniqueConstraints(apply, createTable);
+    if (!pk.isEmpty()) {
+      // defined on the columns
+      writePrimaryKeyConstraint(apply, createTable.getPkName(), toColumnNames(pk));
+    }
+
+    apply.newLine().append(")").endOfStatement();
+
+    writeUniqueOneToOneConstraints(writer, createTable);
+
+    if (isTrue(createTable.isWithHistory())) {
+      // create history with rollback before the
+      // associated drop table is written to rollback
+      createWithHistory(writer, createTable.getName());
+    }
+
+    // add drop table to the rollback buffer - do this before
+    // we drop the related sequence (if sequences are used)
+    dropTable(writer.rollback(), tableName);
+
+    if (useSequence) {
+      String pkCol = pk.get(0).getName();
+      writeSequence(writer, createTable, pkCol);
+    }
+
+    // add blank line for a bit of whitespace between tables
+    apply.end();
+    writer.rollback().end();
+
+    writeAddForeignKeys(writer, createTable);
+
+  }
+
+  private void writeTableColumns(DdlBuffer apply, List<Column> columns, boolean useIdentity) throws IOException {
+    platformDdl.writeTableColumns(apply, columns, useIdentity);
+  }
+
+  /**
+   * Specific handling of OneToOne unique constraints for MsSqlServer.
+   * For all other DB platforms these unique constraints are done inline as per normal.
+   */
+  protected void writeUniqueOneToOneConstraints(DdlWrite write, CreateTable createTable) throws IOException {
+
+    String tableName = createTable.getName();
+    for (Column col : externalUnique) {
+      String uqName = col.getUniqueOneToOne();
+      String[] columnNames = {col.getName()};
+      write.apply()
+          .append(platformDdl.alterTableAddUniqueConstraint(tableName, uqName, columnNames))
+          .endOfStatement();
+
+      write.rollbackForeignKeys()
+          .append(platformDdl.dropIndex(uqName, tableName))
+          .endOfStatement();
+    }
+  }
+
+  protected void writeSequence(DdlWrite writer, CreateTable createTable, String pk) throws IOException {
+
+    // explicit sequence use or platform decides
+    String explicitSequenceName = createTable.getSequenceName();
+    int initial = toInt(createTable.getSequenceInitial());
+    int allocate = toInt(createTable.getSequenceAllocate());
+
+    String seqName = explicitSequenceName;
+    if (seqName == null) {
+      seqName = namingConvention.getSequenceName(createTable.getName(), pk);
+    }
+
+    String createSeq = platformDdl.createSequence(seqName, initial, allocate);
+    if (createSeq != null) {
+      writer.apply().append(createSeq).newLine();
+      writer.rollback().append(platformDdl.dropSequence(seqName)).endOfStatement();
+    }
+  }
+
+  protected void createWithHistory(DdlWrite writer, String name) throws IOException {
+
+    MTable table = writer.getTable(name);
+    platformDdl.createWithHistory(writer, table);
+  }
+
+  protected void writeAddForeignKeys(DdlWrite write, CreateTable createTable) throws IOException {
+
+    String tableName = createTable.getName();
+    List<Column> columns = createTable.getColumn();
+    for (Column column : columns) {
+      String references = column.getReferences();
+      if (hasValue(references)) {
+        writeForeignKey(write, tableName, column);
+      }
+    }
+
+    writeAddCompoundForeignKeys(write, createTable);
+  }
+
+  protected void writeAddCompoundForeignKeys(DdlWrite write, CreateTable createTable) throws IOException {
+
+    String tableName = createTable.getName();
+
+    List<ForeignKey> foreignKey = createTable.getForeignKey();
+    for (ForeignKey key : foreignKey) {
+
+      String refTableName = key.getRefTableName();
+      String fkName = key.getName();
+      String[] cols = toColumnNamesSplit(key.getColumnNames());
+      String[] refColumns = toColumnNamesSplit(key.getRefColumnNames());
+
+      writeForeignKey(write, fkName, tableName, cols, refTableName, refColumns, key.getIndexName());
+    }
+  }
+
+  protected void writeForeignKey(DdlWrite write, String tableName, Column column) throws IOException {
+
+    String fkName = column.getForeignKeyName();
+    String references = column.getReferences();
+    int pos = references.lastIndexOf('.');
+    if (pos == -1) {
+      throw new IllegalStateException("Expecting period '.' character for table.column split but not found in [" + references + "]");
+    }
+    String refTableName = references.substring(0, pos);
+    String refColumnName = references.substring(pos + 1);
+
+    String[] cols = {column.getName()};
+    String[] refCols = {refColumnName};
+
+    writeForeignKey(write, fkName, tableName, cols, refTableName, refCols, column.getForeignKeyIndex());
+  }
+
+  protected void writeForeignKey(DdlWrite write, String fkName, String tableName, String[] columns, String refTable, String[] refColumns, String indexName) throws IOException {
+
+    tableName = lowerName(tableName);
+    DdlBuffer fkeyBuffer = write.applyForeignKeys();
+    alterTableAddForeignKey(fkeyBuffer, fkName, tableName, columns, refTable, refColumns);
+
+    if (indexName != null) {
+      // no matching unique constraint so add the index
+      fkeyBuffer.append(platformDdl.createIndex(indexName, tableName, columns)).endOfStatement();
+    }
+
+    fkeyBuffer.end();
+
+    write.rollbackForeignKeys()
+        .append(platformDdl.alterTableDropForeignKey(tableName, fkName)).endOfStatement();
+
+    if (indexName != null) {
+      write.rollbackForeignKeys()
+          .append(platformDdl.dropIndex(indexName, tableName)).endOfStatement();
+    }
+
+    write.rollbackForeignKeys().end();
+
+  }
+
+  protected void alterTableAddForeignKey(DdlBuffer buffer, String fkName, String tableName, String[] columns, String refTable, String[] refColumns) throws IOException {
+
+    buffer.append(platformDdl.alterTableAddForeignKey(tableName, fkName, columns, refTable, refColumns)).endOfStatement();
+  }
+
+  protected void appendColumns(String[] columns, DdlBuffer buffer) throws IOException {
+    buffer.append(" (");
+    for (int i = 0; i < columns.length; i++) {
+      if (i > 0) {
+        buffer.append(",");
+      }
+      buffer.append(lowerName(columns[i].trim()));
+    }
+    buffer.append(")");
+  }
+
+
+  /**
+   * Add 'drop table' statement to the buffer.
+   */
+  protected void dropTable(DdlBuffer buffer, String tableName) throws IOException {
+
+    buffer.append(platformDdl.dropTable(tableName)).endOfStatement();
+  }
+
+  /**
+   * Write all the check constraints.
+   */
+  protected void writeCheckConstraints(DdlBuffer apply, CreateTable createTable) throws IOException {
+
+    List<Column> columns = createTable.getColumn();
+    for (Column column : columns) {
+      String checkConstraint = column.getCheckConstraint();
+      if (hasValue(checkConstraint)) {
+        writeCheckConstraint(apply, column, checkConstraint);
+      }
+    }
+  }
+
+  /**
+   * Write a check constraint.
+   */
+  protected void writeCheckConstraint(DdlBuffer buffer, Column column, String checkConstraint) throws IOException {
+
+    String ckName = column.getCheckConstraintName();
+
+    buffer.append(",").newLine();
+    buffer.append("  constraint ").append(ckName);
+    buffer.append(" ").append(checkConstraint);
+  }
+
+  protected void writeCompoundUniqueConstraints(DdlBuffer apply, CreateTable createTable) throws IOException {
+
+    List<UniqueConstraint> uniqueConstraints = createTable.getUniqueConstraint();
+    for (UniqueConstraint uniqueConstraint : uniqueConstraints) {
+      String uqName = uniqueConstraint.getName();
+      String[] columns = toColumnNamesSplit(uniqueConstraint.getColumnNames());
+      apply.append(",").newLine();
+      apply.append("  constraint ").append(uqName).append(" unique");
+      appendColumns(columns, apply);
+    }
+  }
+
+  /**
+   * Write the unique constraints inline with the create table statement.
+   */
+  protected void writeUniqueConstraints(DdlBuffer apply, CreateTable createTable) throws IOException {
+
+    boolean inlineUniqueOneToOne = platformDdl.isInlineUniqueOneToOne();
+
+    List<Column> columns = createTable.getColumn();
+    for (Column column : columns) {
+      if (hasValue(column.getUnique()) || (inlineUniqueOneToOne && hasValue(column.getUniqueOneToOne()))) {
+        // normal mechanism for adding unique constraint
+        inlineUniqueConstraintSingle(apply, column);
+
+      } else if (!inlineUniqueOneToOne && hasValue(column.getUniqueOneToOne())) {
+        // MsSqlServer specific mechanism for adding unique constraints (that allow nulls)
+        externalUnique.add(column);
+      }
+    }
+  }
+
+  /**
+   * Write the unique constraint inline with the create table statement.
+   */
+  protected void inlineUniqueConstraintSingle(DdlBuffer buffer, Column column) throws IOException {
+
+    String uqName = column.getUnique();
+    if (uqName == null) {
+      uqName = column.getUniqueOneToOne();
+    }
+
+    buffer.append(",").newLine();
+    buffer.append("  constraint ").append(uqName).append(" unique ");
+    buffer.append("(");
+    buffer.append(lowerName(column.getName()));
+    buffer.append(")");
+  }
+
+  /**
+   * Write the primary key constraint inline with the create table statement.
+   */
+  protected void writePrimaryKeyConstraint(DdlBuffer buffer, String pkName, String[] pkColumns) throws IOException {
+
+    buffer.append(",").newLine();
+    buffer.append("  constraint ").append(pkName).append(" primary key");
+    appendColumns(pkColumns, buffer);
+  }
+
+  /**
+   * Return as an array of string column names.
+   */
+  protected String[] toColumnNames(List<Column> columns) {
+
+    String[] cols = new String[columns.size()];
+    for (int i = 0; i < cols.length; i++) {
+      cols[i] = columns.get(i).getName();
+    }
+    return cols;
+  }
+
+  /**
+   * Return as an array of string column names.
+   */
+  protected String[] toColumnNamesSplit(String columns) {
+    return columns.split(",");
+  }
+
+  /**
+   * Convert the table or column name to lower case.
+   * <p>
+   * This is passed up to the platformDdl to override as desired.
+   * Generally lower case with underscore is a good cross database
+   * choice for column/table names.
+   */
+  protected String lowerName(String name) {
+    return naming.lowerName(name);
+  }
+
+  /**
+   * Return the list of columns that make the primary key.
+   */
+  protected List<Column> determinePrimaryKeyColumns(List<Column> columns) {
+    List<Column> pk = new ArrayList<Column>(3);
+    for (Column column : columns) {
+      if (isTrue(column.isPrimaryKey())) {
+        pk.add(column);
+      }
+    }
+    return pk;
+  }
+
+  @Override
+  public void generate(DdlWrite writer, CreateIndex createIndex) throws IOException {
+
+    String[] cols = toColumnNamesSplit(createIndex.getColumns());
+    writer.apply()
+        .append(platformDdl.createIndex(createIndex.getIndexName(), createIndex.getTableName(), cols))
+        .endOfStatement();
+
+    writer.rollback()
+        .append(platformDdl.dropIndex(createIndex.getIndexName(), createIndex.getTableName()))
+        .endOfStatement();
+  }
+
+  @Override
+  public void generate(DdlWrite writer, DropIndex dropIndex) throws IOException {
+
+    writer.apply()
+        .append(platformDdl.dropIndex(dropIndex.getIndexName(), dropIndex.getTableName()))
+        .endOfStatement();
+  }
+
+  /**
+   * Add add history table DDL.
+   */
+  @Override
+  public void generate(DdlWrite writer, AddHistoryTable addHistoryTable) throws IOException {
+    platformDdl.addHistoryTable(writer, addHistoryTable);
+  }
+
+  /**
+   * Add drop history table DDL.
+   */
+  @Override
+  public void generate(DdlWrite writer, DropHistoryTable dropHistoryTable) throws IOException {
+    platformDdl.dropHistoryTable(writer, dropHistoryTable);
+  }
+
+  /**
+   * Called at the end to generate additional ddl such as regenerate history triggers.
+   */
+  @Override
+  public void generateExtra(DdlWrite write) throws IOException {
+    for (HistoryTableUpdate update : this.regenerateHistoryTriggers.values()) {
+      platformDdl.regenerateHistoryTriggers(write, update);
+    }
+  }
+
+  /**
+   * Add add column DDL.
+   */
+  @Override
+  public void generate(DdlWrite writer, AddColumn addColumn) throws IOException {
+
+    String tableName = addColumn.getTableName();
+    List<Column> columns = addColumn.getColumn();
+    for (Column column : columns) {
+      alterTableAddColumn(writer.apply(), tableName, column, false);
+      alterTableDropColumn(writer.rollback(), tableName, column.getName());
+    }
+
+    if (isTrue(addColumn.isWithHistory())) {
+      // make same changes to the history table
+      String historyTable = historyTable(tableName);
+      for (Column column : columns) {
+        regenerateHistoryTriggers(tableName, HistoryTableUpdate.Change.ADD, column.getName());
+        alterTableAddColumn(writer.apply(), historyTable, column, true);
+        alterTableDropColumn(writer.rollback(), historyTable, column.getName());
+      }
+    }
+
+    // add a bit of whitespace
+    writer.apply().end();
+    writer.rollback().end();
+  }
+
+  /**
+   * Add drop table DDL.
+   */
+  @Override
+  public void generate(DdlWrite writer, DropTable dropTable) throws IOException {
+
+    dropTable(writer.drop(), dropTable.getName());
+  }
+
+  /**
+   * Add drop column DDL.
+   */
+  @Override
+  public void generate(DdlWrite writer, DropColumn dropColumn) throws IOException {
+
+    String tableName = dropColumn.getTableName();
+
+    alterTableDropColumn(writer.drop(), tableName, dropColumn.getColumnName());
+    if (isTrue(dropColumn.isWithHistory())) {
+      // also drop from the history table
+      regenerateHistoryTriggers(tableName, HistoryTableUpdate.Change.DROP, dropColumn.getColumnName());
+      alterTableDropColumn(writer.drop(), historyTable(tableName), dropColumn.getColumnName());
+    }
+
+    writer.drop().end();
+  }
+
+  /**
+   * Add all the appropriate changes based on the column changes.
+   */
+  @Override
+  public void generate(DdlWrite writer, AlterColumn alterColumn) throws IOException {
+
+    if (isTrue(alterColumn.isHistoryExclude())) {
+      regenerateHistoryTriggers(alterColumn.getTableName(), HistoryTableUpdate.Change.EXCLUDE, alterColumn.getColumnName());
+    } else if (isFalse(alterColumn.isHistoryExclude())) {
+      regenerateHistoryTriggers(alterColumn.getTableName(), HistoryTableUpdate.Change.INCLUDE, alterColumn.getColumnName());
+    }
+
+    if (hasValue(alterColumn.getDropForeignKey())) {
+      alterColumnDropForeignKey(writer, alterColumn);
+    }
+    if (hasValue(alterColumn.getReferences())) {
+      alterColumnAddForeignKey(writer, alterColumn);
+    }
+
+    if (hasValue(alterColumn.getDropUnique())) {
+      alterColumnDropUniqueConstraint(writer, alterColumn);
+    }
+    if (hasValue(alterColumn.getUnique())) {
+      alterColumnAddUniqueConstraint(writer, alterColumn);
+    }
+    if (hasValue(alterColumn.getUniqueOneToOne())) {
+      alterColumnAddUniqueOneToOneConstraint(writer, alterColumn);
+    }
+
+    boolean alterBaseAttributes = false;
+    if (hasValue(alterColumn.getType())) {
+      alterColumnType(writer, alterColumn);
+      alterBaseAttributes = true;
+    }
+    if (hasValue(alterColumn.getDefaultValue())) {
+      alterColumnDefaultValue(writer, alterColumn);
+      alterBaseAttributes = true;
+    }
+    if (alterColumn.isNotnull() != null) {
+      alterColumnNotnull(writer, alterColumn);
+      alterBaseAttributes = true;
+    }
+
+    if (alterBaseAttributes) {
+      alterColumnBaseAttributes(writer, alterColumn);
+    }
+  }
+
+  /**
+   * Return the name of the history table given the base table name.
+   */
+  protected String historyTable(String baseTable) {
+    return baseTable + historyTableSuffix;
+  }
+
+  /**
+   * Register the base table that we need to regenerate the history triggers on.
+   */
+  protected void regenerateHistoryTriggers(String baseTableName, HistoryTableUpdate.Change change, String column) {
+
+    HistoryTableUpdate update = regenerateHistoryTriggers.get(baseTableName);
+    if (update == null) {
+      update = new HistoryTableUpdate(baseTableName);
+      regenerateHistoryTriggers.put(baseTableName, update);
+    }
+    update.add(change, column);
+  }
+
+  /**
+   * This is mysql specific - alter all the base attributes of the column together.
+   */
+  protected void alterColumnBaseAttributes(DdlWrite writer, AlterColumn alter) throws IOException {
+
+    String ddl = platformDdl.alterColumnBaseAttributes(alter);
+    if (hasValue(ddl)) {
+      writer.apply().append(ddl).endOfStatement();
+
+      // reverse and generate the rollback statement
+      String currentType = alter.getCurrentType();
+      String type = alter.getType();
+      Boolean currentNotnull = alter.isCurrentNotnull();
+      Boolean notnull = alter.isNotnull();
+
+      alter.setCurrentType(type);
+      alter.setType(currentType);
+      alter.setNotnull(currentNotnull);
+      alter.setCurrentNotnull(notnull);
+
+      // write the rollback
+      ddl = platformDdl.alterColumnBaseAttributes(alter);
+      writer.rollback().append(ddl).endOfStatement();
+
+      if (isTrue(alter.isWithHistory()) && alter.getType() != null) {
+        // mysql and sql server column type change allowing nulls in the history table column
+        AlterColumn alterHistoryColumn = new AlterColumn();
+        alterHistoryColumn.setTableName(historyTable(alter.getTableName()));
+        alterHistoryColumn.setColumnName(alter.getColumnName());
+        alterHistoryColumn.setType(alter.getType());
+        String histColumnDdl = platformDdl.alterColumnBaseAttributes(alterHistoryColumn);
+
+        // write the apply to history table
+        writer.apply().append(histColumnDdl).endOfStatement();
+
+        // write the rollback from history table
+        alterHistoryColumn.setType(currentType);
+        histColumnDdl = platformDdl.alterColumnBaseAttributes(alterHistoryColumn);
+        writer.rollback().append(histColumnDdl).endOfStatement();
+      }
+    }
+  }
+
+  protected void alterColumnDefaultValue(DdlWrite writer, AlterColumn alter) throws IOException {
+
+    String ddl = platformDdl.alterColumnDefaultValue(alter.getTableName(), alter.getColumnName(), alter.getDefaultValue());
+    if (hasValue(ddl)) {
+      writer.apply().append(ddl).endOfStatement();
+    }
+  }
+
+  protected void alterColumnNotnull(DdlWrite writer, AlterColumn alter) throws IOException {
+
+    String ddl = platformDdl.alterColumnNotnull(alter.getTableName(), alter.getColumnName(), alter.isNotnull());
+    if (hasValue(ddl)) {
+      writer.apply().append(ddl).endOfStatement();
+      ddl = platformDdl.alterColumnNotnull(alter.getTableName(), alter.getColumnName(), alter.isCurrentNotnull());
+      writer.rollback().append(ddl).endOfStatement();
+    }
+  }
+
+  protected void alterColumnType(DdlWrite writer, AlterColumn alter) throws IOException {
+
+    String ddl = platformDdl.alterColumnType(alter.getTableName(), alter.getColumnName(), alter.getType());
+    if (hasValue(ddl)) {
+      writer.apply().append(ddl).endOfStatement();
+      ddl = platformDdl.alterColumnType(alter.getTableName(), alter.getColumnName(), alter.getCurrentType());
+      writer.rollback().append(ddl).endOfStatement();
+      if (isTrue(alter.isWithHistory())) {
+        // apply same type change to matching column in the history table
+        ddl = platformDdl.alterColumnType(historyTable(alter.getTableName()), alter.getColumnName(), alter.getType());
+        writer.apply().append(ddl).endOfStatement();
+        ddl = platformDdl.alterColumnType(historyTable(alter.getTableName()), alter.getColumnName(), alter.getCurrentType());
+        writer.rollback().append(ddl).endOfStatement();
+      }
+    }
+  }
+
+
+  protected void alterColumnAddForeignKey(DdlWrite writer, AlterColumn alterColumn) throws IOException {
+
+    String tableName = alterColumn.getTableName();
+    String fkName = alterColumn.getForeignKeyName();
+    String[] cols = {alterColumn.getColumnName()};
+    String references = alterColumn.getReferences();
+    int pos = references.lastIndexOf('.');
+    if (pos == -1) {
+      throw new IllegalStateException("Expecting period '.' character for table.column split but not found in [" + references + "]");
+    }
+    String refTableName = references.substring(0, pos);
+    String refColumnName = references.substring(pos + 1);
+    String[] refCols = {refColumnName};
+
+    alterTableAddForeignKey(writer.apply(), fkName, tableName, cols, refTableName, refCols);
+  }
+
+  protected void alterColumnDropForeignKey(DdlWrite writer, AlterColumn alter) throws IOException {
+
+    writer.apply()
+        .append(platformDdl.alterTableDropForeignKey(alter.getTableName(), alter.getDropForeignKey()))
+        .endOfStatement();
+  }
+
+
+  protected void alterColumnDropUniqueConstraint(DdlWrite writer, AlterColumn alter) throws IOException {
+
+    writer.apply()
+        .append(platformDdl.alterTableDropUniqueConstraint(alter.getTableName(), alter.getDropUnique()))
+        .endOfStatement();
+  }
+
+  protected void alterColumnAddUniqueOneToOneConstraint(DdlWrite writer, AlterColumn alter) throws IOException {
+
+    addUniqueConstraint(writer, alter, alter.getUniqueOneToOne());
+  }
+
+  protected void alterColumnAddUniqueConstraint(DdlWrite writer, AlterColumn alter) throws IOException {
+
+    addUniqueConstraint(writer, alter, alter.getUnique());
+  }
+
+  protected void addUniqueConstraint(DdlWrite writer, AlterColumn alter, String uqName) throws IOException {
+
+    String[] cols = {alter.getColumnName()};
+
+    writer.apply()
+        .append(platformDdl.alterTableAddUniqueConstraint(alter.getTableName(), uqName, cols))
+        .endOfStatement();
+
+    writer.rollbackForeignKeys()
+        .append(platformDdl.dropIndex(uqName, alter.getTableName()))
+        .endOfStatement();
+  }
+
+
+  protected void alterTableDropColumn(DdlBuffer buffer, String tableName, String columnName) throws IOException {
+
+    buffer.append("alter table ").append(tableName).append(" drop column ").append(columnName)
+        .endOfStatement();
+  }
+
+  protected void alterTableAddColumn(DdlBuffer buffer, String tableName, Column column, boolean onHistoryTable) throws IOException {
+
+    buffer.append("alter table ").append(tableName)
+        .append(" add column ").append(column.getName())
+        .append(" ").append(column.getType());
+
+    if (!onHistoryTable) {
+      if (isTrue(column.isNotnull())) {
+        buffer.append(" not null");
+      }
+      if (hasValue(column.getCheckConstraint())) {
+        buffer.append(" ").append(column.getCheckConstraint());
+      }
+    }
+    buffer.endOfStatement();
+  }
+
+  protected boolean isFalse(Boolean value) {
+    return value != null && !value;
+  }
+
+  /**
+   * Return true if null or trimmed string is empty.
+   */
+  protected boolean hasValue(String value) {
+    return value != null && !value.trim().isEmpty();
+  }
+
+  /**
+   * Null safe Boolean true test.
+   */
+  protected boolean isTrue(Boolean value) {
+    return Boolean.TRUE.equals(value);
+  }
+
+  /**
+   * Return as an int value with 0 when it is null.
+   */
+  protected int toInt(BigInteger value) {
+    return (value == null) ? 0 : value.intValue();
+  }
+
+}

src/main/java/com/avaje/ebean/dbmigration/ddlgeneration/platform/DB2Ddl.java

@@ -0,0 +1,16 @@
+package com.avaje.ebean.dbmigration.ddlgeneration.platform;
+
+import com.avaje.ebean.config.dbplatform.DbIdentity;
+import com.avaje.ebean.config.dbplatform.DbTypeMap;
+
+/**
+ * DB2 platform specific DDL.
+ */
+public class DB2Ddl extends PlatformDdl {
+
+  public DB2Ddl(DbTypeMap platformTypes, DbIdentity dbIdentity) {
+    super(platformTypes, dbIdentity);
+    this.identitySuffix = " generated by default as identity";
+  }
+
+}

src/main/java/com/avaje/ebean/dbmigration/ddlgeneration/platform/DbTriggerBasedHistoryDdl.java

@@ -0,0 +1,241 @@
+package com.avaje.ebean.dbmigration.ddlgeneration.platform;
+
+import com.avaje.ebean.config.DbConstraintNaming;
+import com.avaje.ebean.config.ServerConfig;
+import com.avaje.ebean.dbmigration.ddlgeneration.DdlBuffer;
+import com.avaje.ebean.dbmigration.ddlgeneration.DdlWrite;
+import com.avaje.ebean.dbmigration.migration.AddHistoryTable;
+import com.avaje.ebean.dbmigration.migration.DropHistoryTable;
+import com.avaje.ebean.dbmigration.model.MColumn;
+import com.avaje.ebean.dbmigration.model.MTable;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+
+/**
+ * Uses DB triggers to maintain a history table.
+ */
+public abstract class DbTriggerBasedHistoryDdl implements PlatformHistoryDdl {
+
+  protected DbConstraintNaming constraintNaming;
+
+  protected PlatformDdl platformDdl;
+
+  protected String sysPeriod;
+  protected String sysPeriodStart;
+  protected String sysPeriodEnd;
+
+  protected String viewSuffix;
+  protected String historySuffix;
+
+
+  protected String currentTimestamp = "now(6)";
+  protected String sysPeriodType = "datetime(6)";
+
+  public DbTriggerBasedHistoryDdl() {
+  }
+
+  @Override
+  public void configure(ServerConfig serverConfig, PlatformDdl platformDdl) {
+    this.platformDdl = platformDdl;
+    this.sysPeriod = serverConfig.getAsOfSysPeriod();
+    this.viewSuffix = serverConfig.getAsOfViewSuffix();
+    this.historySuffix = serverConfig.getHistoryTableSuffix();
+    this.constraintNaming = serverConfig.getConstraintNaming();
+
+    this.sysPeriodStart = sysPeriod+"_start";
+    this.sysPeriodEnd = sysPeriod+"_end";
+  }
+
+  @Override
+  public void regenerateHistoryTriggers(DdlWrite writer, HistoryTableUpdate update) throws IOException {
+
+    MTable table = writer.getTable(update.getBaseTable());
+    if (table == null) {
+      throw new IllegalStateException("MTable "+update.getBaseTable()+" not found in writer? (required for history DDL)");
+    }
+    regenerateHistoryTriggers(writer, table, update);
+  }
+
+  protected abstract void regenerateHistoryTriggers(DdlWrite writer, MTable table, HistoryTableUpdate update) throws IOException;
+
+  @Override
+  public void dropHistoryTable(DdlWrite writer, DropHistoryTable dropHistoryTable) throws IOException {
+
+    String baseTable = dropHistoryTable.getBaseTable();
+
+    // drop in appropriate order
+    dropTriggers(writer.dropHistory(), baseTable);
+    dropHistoryTableEtc(writer.dropHistory(), baseTable);
+  }
+
+
+  @Override
+  public void addHistoryTable(DdlWrite writer, AddHistoryTable addHistoryTable) throws IOException {
+
+    String baseTable = addHistoryTable.getBaseTable();
+    MTable table = writer.getTable(baseTable);
+    if (table == null) {
+      throw new IllegalStateException("MTable "+baseTable+" not found in writer? (required for history DDL)");
+    }
+
+    createWithHistory(writer, table);
+  }
+
+  @Override
+  public void createWithHistory(DdlWrite writer, MTable table) throws IOException {
+
+    String baseTable = table.getName();
+    String whenCreatedColumn = table.getWhenCreatedColumn();
+
+    // rollback changes in appropriate order
+    dropTriggers(writer.rollback(), baseTable);
+    dropHistoryTableEtc(writer.rollback(), baseTable);
+
+    addHistoryTable(writer, table, whenCreatedColumn);
+    addStoredFunction(writer, table, null);
+    createTriggers(writer, table);
+  }
+
+  protected abstract void createTriggers(DdlWrite writer, MTable table) throws IOException;
+
+  protected abstract void dropTriggers(DdlBuffer buffer, String baseTable) throws IOException;
+
+  protected void addStoredFunction(DdlWrite writer, MTable table, HistoryTableUpdate update) throws IOException {
+    // do nothing
+  }
+
+  protected String normalise(String tableName) {
+    return constraintNaming.normaliseTable(tableName);
+  }
+
+  protected String historyTableName(String baseTableName) {
+    return normalise(baseTableName) + historySuffix;
+  }
+
+  protected String procedureName(String baseTableName) {
+    return normalise(baseTableName) + "_history_version";
+  }
+
+  protected String triggerName(String baseTableName) {
+    return normalise(baseTableName) + "_history_upd";
+  }
+
+  protected String updateTriggerName(String baseTableName) {
+    return normalise(baseTableName) + "_history_upd";
+  }
+
+  protected String deleteTriggerName(String baseTableName) {
+    return normalise(baseTableName) + "_history_del";
+  }
+
+  protected void addHistoryTable(DdlWrite writer, MTable table, String whenCreatedColumn) throws IOException {
+
+    String baseTableName = table.getName();
+
+    DdlBuffer apply = writer.applyHistory();
+
+    addSysPeriodColumns(apply, baseTableName, whenCreatedColumn);
+    createHistoryTable(apply, table);
+    createWithHistoryView(apply, baseTableName);
+  }
+
+  protected void addSysPeriodColumns(DdlBuffer apply, String baseTableName, String whenCreatedColumn) throws IOException {
+
+    apply.append("alter table ").append(baseTableName).append(" add column ")
+        .append(sysPeriodStart).append(" ").append(sysPeriodType).append(" default ").append(currentTimestamp).endOfStatement();
+    apply.append("alter table ").append(baseTableName).append(" add column ")
+        .append(sysPeriodEnd).append(" ").append(sysPeriodType).endOfStatement();
+
+    if (whenCreatedColumn != null) {
+      apply.append("update ").append(baseTableName).append(" set ").append(sysPeriodStart).append(" = ").append(whenCreatedColumn).endOfStatement();
+    }
+  }
+
+  protected void createHistoryTable(DdlBuffer apply, MTable table) throws IOException {
+
+    apply.append("create table ").append(table.getName()).append(historySuffix).append("(").newLine();
+
+    Collection<MColumn> cols = table.getColumns().values();
+    for (MColumn column : cols) {
+      writeColumnDefinition(apply, column.getName(), column.getType());
+      apply.append(",").newLine();
+    }
+    writeColumnDefinition(apply, sysPeriodStart, sysPeriodType);
+    apply.append(",").newLine();
+    writeColumnDefinition(apply, sysPeriodEnd, sysPeriodType);
+    apply.newLine().append(")").endOfStatement();
+  }
+
+  /**
+   * Write the column definition to the create table statement.
+   */
+  protected void writeColumnDefinition(DdlBuffer buffer, String columnName, String type) throws IOException {
+
+    String platformType = platformDdl.convert(type, false);
+    buffer.append("  ");
+    buffer.append(platformDdl.lowerName(columnName), 30);
+    buffer.append(platformType);
+  }
+
+  protected void createWithHistoryView(DdlBuffer apply, String baseTableName) throws IOException {
+
+    apply
+        .append("create view ").append(baseTableName).append(viewSuffix)
+        .append(" as select * from ").append(baseTableName)
+        .append(" union all select * from ").append(baseTableName).append(historySuffix)
+        .endOfStatement().end();
+  }
+
+  protected void dropHistoryTableEtc(DdlBuffer buffer, String baseTableName) throws IOException {
+
+    buffer.append("drop view ").append(baseTableName).append(viewSuffix).endOfStatement();
+    dropSysPeriodColumns(buffer, baseTableName);
+    buffer.append("drop table ").append(baseTableName).append(historySuffix).endOfStatement().end();
+  }
+
+  protected void dropSysPeriodColumns(DdlBuffer buffer, String baseTableName) throws IOException {
+    buffer.append("alter table ").append(baseTableName).append(" drop column ").append(sysPeriodStart).endOfStatement();
+    buffer.append("alter table ").append(baseTableName).append(" drop column ").append(sysPeriodEnd).endOfStatement();
+  }
+
+  //protected abstract void addFunction(DdlBuffer apply, String procedureName, String historyTable, List<String> includedColumns) throws IOException;
+
+  protected void appendInsertIntoHistory(DdlBuffer buffer, String historyTable, List<String> columns) throws IOException {
+
+    buffer.append("    insert into ").append(historyTable).append(" (").append(sysPeriodStart).append(",").append(sysPeriodEnd).append(",");
+    appendColumnNames(buffer, columns, "");
+    buffer.append(") values (OLD.").append(sysPeriodStart).append(", ").append(currentTimestamp).append(",");
+    appendColumnNames(buffer, columns, "OLD.");
+    buffer.append(");").newLine();
+  }
+
+  protected void appendColumnNames(DdlBuffer buffer, List<String> columns, String columnPrefix) throws IOException {
+
+    for (int i=0; i< columns.size(); i++) {
+      if (i > 0) {
+        buffer.append(", ");
+      }
+      buffer.append(columnPrefix);
+      buffer.append(columns.get(i));
+    }
+  }
+
+  /**
+   * Return the list of included columns in order.
+   */
+  protected List<String> includedColumnNames(MTable table) throws IOException {
+
+    Collection<MColumn> columns = table.getColumns().values();
+    List<String> includedColumns = new ArrayList<String>(columns.size());
+
+    for (MColumn column : columns) {
+      if (!column.isHistoryExclude()) {
+        includedColumns.add(column.getName());
+      }
+    }
+    return includedColumns;
+  }
+}

src/main/java/com/avaje/ebean/dbmigration/ddlgeneration/platform/DefaultConstraintMaxLength.java

@@ -0,0 +1,37 @@
+package com.avaje.ebean.dbmigration.ddlgeneration.platform;
+
+import com.avaje.ebean.config.DbConstraintNaming;
+import com.avaje.ebean.dbmigration.ddlgeneration.platform.util.VowelRemover;
+
+/**
+ * Default implementation used to truncate or shorten db constraint names as required.
+ */
+public class DefaultConstraintMaxLength implements DbConstraintNaming.MaxLength {
+
+  private final int maxConstraintNameLength;
+
+  public DefaultConstraintMaxLength(int maxConstraintNameLength) {
+    this.maxConstraintNameLength = maxConstraintNameLength;
+  }
+
+  /**
+   * Apply a maximum length to the constraint name.
+   * <p>
+   * This implementation should work well apart from perhaps DB2 where the limit is 18.
+   */
+  public String maxLength(String constraintName, int count) {
+    if (constraintName.length() < maxConstraintNameLength) {
+      return constraintName;
+    }
+    if (maxConstraintNameLength < 60) {
+      // trim out vowels for Oracle / DB2 with short max lengths
+      constraintName = VowelRemover.trim(constraintName, 4);
+      if (constraintName.length() < maxConstraintNameLength) {
+        return constraintName;
+      }
+    }
+    // add the count to ensure the constraint name is unique
+    // (relying on the prefix having the table name to be globally unique)
+    return constraintName.substring(0, maxConstraintNameLength - 3) + "_" + count;
+  }
+}

src/main/java/com/avaje/ebean/dbmigration/ddlgeneration/platform/H2Ddl.java

@@ -0,0 +1,15 @@
+package com.avaje.ebean.dbmigration.ddlgeneration.platform;
+
+import com.avaje.ebean.config.dbplatform.DbIdentity;
+import com.avaje.ebean.config.dbplatform.DbTypeMap;
+
+/**
+ * H2 platform specific DDL.
+ */
+public class H2Ddl extends PlatformDdl {
+
+  public H2Ddl(DbTypeMap platformTypes, DbIdentity dbIdentity) {
+    super(platformTypes, dbIdentity);
+  }
+
+}

src/main/java/com/avaje/ebean/dbmigration/ddlgeneration/platform/HistoryTableUpdate.java

@@ -0,0 +1,109 @@
+package com.avaje.ebean.dbmigration.ddlgeneration.platform;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Bean holding comments relating to a history table that needs to have it's
+ * associated triggers/function updated due to columns added/dropped/included
+ * or excluded.
+ */
+public class HistoryTableUpdate {
+
+
+  /**
+   * Column change type.
+   */
+  public enum Change {
+    ADD,
+    DROP,
+    INCLUDE,
+    EXCLUDE
+  }
+
+  public static class Column {
+
+    public final Change change;
+    public final String column;
+    public Column(Change change, String column) {
+      this.change = change;
+      this.column = column;
+    }
+
+    public String description() {
+      return change.name().toLowerCase()+" "+column;
+    }
+
+    public void apply(List<String> includedColumns) {
+      switch (change) {
+        case ADD:
+        case INCLUDE: {
+          includedColumns.remove(column);
+          break;
+        }
+        case DROP:
+        case EXCLUDE: {
+          includedColumns.add(column);
+          break;
+        }
+        default:
+          throw new IllegalStateException("Unexpected change "+change);
+      }
+    }
+  }
+
+  private final String baseTable;
+
+  private final List<Column> columnChanges = new ArrayList<Column>();
+
+  /**
+   * Construct with a given base table name.
+   */
+  public HistoryTableUpdate(String baseTable) {
+    this.baseTable = baseTable;
+  }
+
+  /**
+   * Return a description of the changes that cause the history trigger/function
+   * to be regenerated (added, dropped, included or excluded columns).
+   */
+  public String description() {
+    StringBuilder sb = new StringBuilder(90);
+    for (int i = 0; i < columnChanges.size(); i++) {
+      if (i > 0) {
+        sb.append(", ");
+      }
+      sb.append(columnChanges.get(i).description());
+    }
+    return sb.toString();
+  }
+
+  public void toRevertedColumns(List<String> includedColumns) {
+
+    for (Column columnChange : columnChanges) {
+      columnChange.apply(includedColumns);
+    }
+  }
+
+
+  /**
+   * Add a comment for column added, dropped, included or excluded.
+   */
+  public void add(Change change, String column) {
+    columnChanges.add(new Column(change, column));
+  }
+
+  /**
+   * Return the base table name.
+   */
+  public String getBaseTable() {
+    return baseTable;
+  }
+
+  /**
+   * Return the comments.
+   */
+  public List<Column> getColumnChanges() {
+    return columnChanges;
+  }
+}

src/main/java/com/avaje/ebean/dbmigration/ddlgeneration/platform/HsqldbDdl.java

@@ -0,0 +1,16 @@
+package com.avaje.ebean.dbmigration.ddlgeneration.platform;
+
+import com.avaje.ebean.config.dbplatform.DbIdentity;
+import com.avaje.ebean.config.dbplatform.DbTypeMap;
+
+/**
+ * Hsqldb platform specific DDL.
+ */
+public class HsqldbDdl extends PlatformDdl {
+
+  public HsqldbDdl(DbTypeMap platformTypes, DbIdentity dbIdentity) {
+    super(platformTypes, dbIdentity);
+    this.identitySuffix = " generated by default as identity (start with 1) ";
+  }
+
+}