WIP: Db migration alterColumn ...

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

@@ -0,0 +1,42 @@
+package com.avaje.ebean.config;
+
+/**
+ * Configuration for the DB migration processing.
+ */
+public class DbMigrationConfig {
+
+  /**
+   * The application name which is used as the unique code when applying migrations.
+   */
+  private String appName;
+
+  /**
+   * Path where migration
+   */
+  private String resourcePath;
+
+  public String getAppName() {
+    return appName;
+  }
+
+  public void setAppName(String appName) {
+    this.appName = appName;
+  }
+
+  public String getResourcePath() {
+    return resourcePath;
+  }
+
+  public void setResourcePath(String resourcePath) {
+    this.resourcePath = resourcePath;
+  }
+
+  /**
+   * Load the settings from the PropertiesWrapper.
+   */
+  public void loadSettings(PropertiesWrapper properties) {
+
+    appName = properties.get("migration.appName", appName);
+    resourcePath = properties.get("migration.resourcePath", resourcePath);
+  }
+}

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

@@ -207,6 +207,11 @@ 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>
@@ -502,7 +507,7 @@ 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>
@@ -620,6 +625,20 @@ public class ServerConfig {
     this.databaseSequenceBatchSize = databaseSequenceBatchSize;
   }
 
+  /**
+   * 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.
@@ -1856,6 +1875,8 @@ public class ServerConfig {
    */
   protected void loadSettings(PropertiesWrapper p) {
 
+    migrationConfig.loadSettings(p);
+
     namingConvention = createNamingConvention(p, namingConvention);
     if (namingConvention != null) {
       namingConvention.loadFromProperties(p);

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

@@ -0,0 +1,56 @@
+package com.avaje.ebean.dbmigration;
+
+import com.avaje.ebean.Ebean;
+import com.avaje.ebean.EbeanServer;
+import com.avaje.ebean.config.DbMigrationConfig;
+import com.avaje.ebean.dbmigration.model.CurrentModel;
+import com.avaje.ebeaninternal.api.SpiEbeanServer;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.File;
+
+/**
+ *
+ */
+public class DbMigration {
+
+  private static final Logger logger = LoggerFactory.getLogger(DbMigration.class);
+
+  private final SpiEbeanServer server;
+
+  private final DbMigrationConfig migrationConfig;
+
+  public DbMigration() {
+    this(Ebean.getDefaultServer());
+  }
+
+  public DbMigration(EbeanServer ebeanServer) {
+    this.server = (SpiEbeanServer) ebeanServer;
+    this.migrationConfig = server.getServerConfig().getMigrationConfig();
+  }
+
+
+
+  public void writeCurrent() {
+
+    CurrentModel currentModel = new CurrentModel(server);
+
+    File writeTo = getWritePath();
+    logger.info("... write to {}", writeTo.getAbsolutePath());
+    currentModel.writeMigration(writeTo);
+  }
+
+  public File getWritePath() {
+    File resourceRootDir = new File("./dbmigration-test/resources");
+
+    // expect to be a relative path
+    String resourcePath = migrationConfig.getResourcePath();
+
+    File path = new File(resourceRootDir, resourcePath);
+    if (!path.exists()) {
+      path.mkdirs();
+    }
+    return new File(path, "migration-current.xml");
+  }
+}

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

@@ -0,0 +1,37 @@
+package com.avaje.ebean.dbmigration;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ *
+ */
+public class DbOffline {
+
+  private static final Logger logger = LoggerFactory.getLogger(DbOffline.class);
+
+  private static final String KEY = "ebean.dboffline";
+
+  public static final String H2 = "H2";
+
+  public static void setPlatform(String platformName) {
+    System.setProperty(KEY, platformName);
+  }
+
+  public static String getPlatform() {
+    return System.getProperty(KEY);
+  }
+
+  public static void asH2() {
+    setPlatform(H2);
+  }
+
+  public static boolean isSet() {
+    return getPlatform() != null;
+  }
+
+  public static void reset() {
+    System.clearProperty(KEY);
+    logger.info("reset");
+  }
+}

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

@@ -5,6 +5,7 @@ import com.avaje.ebean.dbmigration.ddlgeneration.platform.BaseTableDdl;
 import com.avaje.ebean.dbmigration.ddlgeneration.platform.DdlNamingConvention;
 import com.avaje.ebean.dbmigration.ddlgeneration.platform.PlatformDdl;
 import com.avaje.ebean.dbmigration.migration.AddColumn;
+import com.avaje.ebean.dbmigration.migration.AlterColumn;
 import com.avaje.ebean.dbmigration.migration.ChangeSet;
 import com.avaje.ebean.dbmigration.migration.CreateTable;
 import com.avaje.ebean.dbmigration.migration.DropColumn;
@@ -23,7 +24,7 @@ public class BaseDdlHandler implements DdlHandler {
 
   public BaseDdlHandler(DdlNamingConvention namingConvention, PlatformDdl platformDdl) {
     this.tableDdl = new BaseTableDdl(namingConvention, platformDdl);
-    this.columnDdl = new BaseColumnDdl();
+    this.columnDdl = new BaseColumnDdl(platformDdl);
   }
 
   @Override
@@ -37,6 +38,8 @@ public class BaseDdlHandler implements DdlHandler {
         generate(writer, (AddColumn) change);
       } else if (change instanceof DropColumn) {
         generate(writer, (DropColumn) change);
+      } else if (change instanceof AlterColumn) {
+        generate(writer, (AlterColumn) change);
       }
     }
   }
@@ -56,4 +59,8 @@ public class BaseDdlHandler implements DdlHandler {
     columnDdl.generate(writer, dropColumn);
   }
 
+  @Override
+  public void generate(DdlWrite writer, AlterColumn alterColumn) throws IOException {
+    columnDdl.generate(writer, alterColumn);
+  }
 }

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

@@ -1,23 +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 AddColumn or DropColumn.
+ * Write DDL for AddColumn , DropColumn or AlterColumn.
  */
 public interface ColumnDdl {
 
   /**
-   * Write a AddColumn change.
+   * Write the add column change.
    */
   void generate(DdlWrite writer, AddColumn addColumn) throws IOException;
 
   /**
-   * Write a DropColumn change.
+   * 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/DdlHandler.java

@@ -1,6 +1,7 @@
 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.ChangeSet;
 import com.avaje.ebean.dbmigration.migration.CreateTable;
 import com.avaje.ebean.dbmigration.migration.DropColumn;
@@ -18,4 +19,7 @@ public interface DdlHandler {
   void generate(DdlWrite writer, AddColumn addColumn) throws IOException;
 
   void generate(DdlWrite writer, DropColumn dropColumn) throws IOException;
-}
+
+  void generate(DdlWrite writer, AlterColumn alterColumn) throws IOException;
+
+}

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

@@ -4,6 +4,7 @@ import com.avaje.ebean.dbmigration.ddlgeneration.ColumnDdl;
 import com.avaje.ebean.dbmigration.ddlgeneration.DdlBuffer;
 import com.avaje.ebean.dbmigration.ddlgeneration.DdlWrite;
 import com.avaje.ebean.dbmigration.migration.AddColumn;
+import com.avaje.ebean.dbmigration.migration.AlterColumn;
 import com.avaje.ebean.dbmigration.migration.Column;
 import com.avaje.ebean.dbmigration.migration.DropColumn;
 
@@ -14,6 +15,11 @@ import java.util.List;
  */
 public class BaseColumnDdl implements ColumnDdl {
 
+  protected final PlatformDdl platformDdl;
+
+  public BaseColumnDdl(PlatformDdl platformDdl) {
+    this.platformDdl = platformDdl;
+  }
 
   @Override
   public void generate(DdlWrite writer, AddColumn addColumn) throws IOException {
@@ -40,6 +46,89 @@ public class BaseColumnDdl implements ColumnDdl {
     // are put into a separate changeSet that is run last
   }
 
+  @Override
+  public void generate(DdlWrite writer, AlterColumn alterColumn) throws IOException {
+
+    if (isTrue(alterColumn.isHistoryExclude())) {
+      historyExcludeColumn(writer, alterColumn);
+    } else if (isFalse(alterColumn.isHistoryExclude())) {
+      historyIncludeColumn(writer, alterColumn);
+    }
+
+    if (hasValue(alterColumn.getOldReferences())) {
+      dropForeignKey(writer, alterColumn);
+    }
+    if (hasValue(alterColumn.getNewReferences())) {
+      addForeignKey(writer, alterColumn);
+    }
+
+    if (isTrue(alterColumn.isUnique())) {
+      addUniqueConstraint(writer, alterColumn);
+    } else if (isFalse(alterColumn.isUnique())) {
+      dropUniqueConstraint(writer, alterColumn);
+    }
+
+    if (isTrue(alterColumn.isUniqueOneToOne())) {
+      addUniqueOneToOneConstraint(writer, alterColumn);
+    } else if (isFalse(alterColumn.isUniqueOneToOne())) {
+      dropUniqueOneToOneConstraint(writer, alterColumn);
+    }
+
+  }
+
+
+
+  protected void addForeignKey(DdlWrite writer, AlterColumn alterColumn) {
+
+  }
+
+  protected void dropForeignKey(DdlWrite writer, AlterColumn alterColumn) {
+
+  }
+
+  protected void dropUniqueOneToOneConstraint(DdlWrite writer, AlterColumn alterColumn) {
+
+  }
+
+  protected void addUniqueOneToOneConstraint(DdlWrite writer, AlterColumn alterColumn) {
+
+  }
+
+  protected void dropUniqueConstraint(DdlWrite writer, AlterColumn alter) throws IOException {
+
+    String tableName = alter.getTableName();
+    String columnName = alter.getColumnName();
+    String uqName = platformDdl.namingConvention.uniqueConstraintName(tableName, columnName, 50);
+
+    writer.apply()
+        .append(platformDdl.dropIndex(uqName, tableName))
+        .endOfStatement();
+  }
+
+  protected void addUniqueConstraint(DdlWrite writer, AlterColumn alter) throws IOException {
+
+    String tableName = alter.getTableName();
+    String columnName = alter.getColumnName();
+    String uqName = platformDdl.namingConvention.uniqueConstraintName(tableName, columnName, 50);
+
+    String[] cols = {columnName};
+    writer.apply()
+        .append(platformDdl.createExternalUniqueForOneToOne(uqName, tableName, cols))
+        .endOfStatement();
+
+    writer.rollbackForeignKeys()
+        .append(platformDdl.dropIndex(uqName, tableName))
+        .endOfStatement();
+  }
+
+  protected void historyIncludeColumn(DdlWrite writer, AlterColumn alterColumn) {
+    platformDdl.historyIncludeColumn(writer, alterColumn);
+  }
+
+  protected void historyExcludeColumn(DdlWrite writer, AlterColumn alterColumn) {
+    platformDdl.historyExcludeColumn(writer, alterColumn);
+  }
+
   protected void alterTableDropColumn(DdlBuffer buffer, String tableName, String columnName) throws IOException {
 
     buffer.append("alter table ").append(tableName)
@@ -63,6 +152,14 @@ public class BaseColumnDdl implements ColumnDdl {
   }
 
 
+  protected boolean isFalse(Boolean value) {
+    return value != null && !value;
+  }
+
+  protected boolean isTrue(Boolean value) {
+    return value != null && value;
+  }
+
   protected boolean hasValue(String value) {
     return value != null && !value.trim().isEmpty();
   }

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

@@ -356,20 +356,6 @@ public class BaseTableDdl implements TableDdl {
     appendColumns(pkColumns, buffer);
   }
 
-  /**
-   * Write alter table add primary key statement.
-   */
-  public void alterTableAddPrimaryKey(DdlBuffer buffer, String tableName, List<Column> pk) throws IOException {
-
-    String[] pkColumns = toColumnNames(pk);
-    String pkName = determinePrimaryKeyName(tableName);
-
-    buffer.append("alter table ").append(tableName);
-    buffer.append(" add primary key ").append(pkName);
-    appendColumns(pkColumns, buffer);
-    buffer.append(")").endOfStatement();
-  }
-
   /**
    * Return as an array of string column names.
    */

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

@@ -13,6 +13,7 @@ public class MsSqlServerDdl extends PlatformDdl {
     this.identitySuffix = " identity(1,1)";
     this.foreignKeyRestrict = "";
     this.inlineUniqueOneToOne = false;
+    this.namingConvention.maxConstraintNameLength = 62; //Actually 128
   }
 
   @Override

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

@@ -7,6 +7,7 @@ import com.avaje.ebean.dbmigration.ddlgeneration.BaseDdlHandler;
 import com.avaje.ebean.dbmigration.ddlgeneration.DdlHandler;
 import com.avaje.ebean.dbmigration.ddlgeneration.DdlWrite;
 import com.avaje.ebean.dbmigration.ddlgeneration.platform.util.PlatformTypeConverter;
+import com.avaje.ebean.dbmigration.migration.AlterColumn;
 import com.avaje.ebean.dbmigration.migration.IdentityType;
 import com.avaje.ebean.dbmigration.model.MTable;
 
@@ -176,4 +177,12 @@ public class PlatformDdl {
     // does nothing by default, really this is a MsSqlServer specific requirement
     return "";
   }
+
+  public void historyExcludeColumn(DdlWrite writer, AlterColumn alterColumn) {
+
+  }
+
+  public void historyIncludeColumn(DdlWrite writer, AlterColumn alterColumn) {
+
+  }
 }

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

@@ -12,6 +12,7 @@ public class PostgresDdl extends PlatformDdl {
     super(platformTypes, dbIdentity);
     this.historyDdl = new PostgresHistoryDdl(this.namingConvention.normalise);
     this.dropTableCascade = " cascade";
+    this.namingConvention.maxConstraintNameLength = 62;
   }
 
   /**

src/main/java/com/avaje/ebean/dbmigration/migration/AlterColumn.java

@@ -0,0 +1,384 @@
+
+package com.avaje.ebean.dbmigration.migration;
+
+import javax.xml.bind.annotation.XmlAccessType;
+import javax.xml.bind.annotation.XmlAccessorType;
+import javax.xml.bind.annotation.XmlAttribute;
+import javax.xml.bind.annotation.XmlRootElement;
+import javax.xml.bind.annotation.XmlType;
+
+
+/**
+ * <p>Java class for anonymous complex type.
+ * 
+ * <p>The following schema fragment specifies the expected content contained within this class.
+ * 
+ * <pre>
+ * &lt;complexType>
+ *   &lt;complexContent>
+ *     &lt;restriction base="{http://www.w3.org/2001/XMLSchema}anyType">
+ *       &lt;attribute name="columnName" use="required" type="{http://www.w3.org/2001/XMLSchema}string" />
+ *       &lt;attribute name="tableName" use="required" type="{http://www.w3.org/2001/XMLSchema}string" />
+ *       &lt;attribute name="type" type="{http://www.w3.org/2001/XMLSchema}string" />
+ *       &lt;attribute name="notnull" type="{http://www.w3.org/2001/XMLSchema}boolean" />
+ *       &lt;attribute name="historyExclude" type="{http://www.w3.org/2001/XMLSchema}boolean" />
+ *       &lt;attribute name="unique" type="{http://www.w3.org/2001/XMLSchema}boolean" />
+ *       &lt;attribute name="uniqueOneToOne" type="{http://www.w3.org/2001/XMLSchema}boolean" />
+ *       &lt;attribute name="oldDefaultValue" type="{http://www.w3.org/2001/XMLSchema}string" />
+ *       &lt;attribute name="newDefaultValue" type="{http://www.w3.org/2001/XMLSchema}string" />
+ *       &lt;attribute name="oldCheckConstraint" type="{http://www.w3.org/2001/XMLSchema}string" />
+ *       &lt;attribute name="newCheckConstraint" type="{http://www.w3.org/2001/XMLSchema}string" />
+ *       &lt;attribute name="oldReferences" type="{http://www.w3.org/2001/XMLSchema}string" />
+ *       &lt;attribute name="newReferences" type="{http://www.w3.org/2001/XMLSchema}string" />
+ *     &lt;/restriction>
+ *   &lt;/complexContent>
+ * &lt;/complexType>
+ * </pre>
+ * 
+ * 
+ */
+@XmlAccessorType(XmlAccessType.FIELD)
+@XmlType(name = "")
+@XmlRootElement(name = "alterColumn")
+public class AlterColumn {
+
+    @XmlAttribute(name = "columnName", required = true)
+    protected String columnName;
+    @XmlAttribute(name = "tableName", required = true)
+    protected String tableName;
+    @XmlAttribute(name = "type")
+    protected String type;
+    @XmlAttribute(name = "notnull")
+    protected Boolean notnull;
+    @XmlAttribute(name = "historyExclude")
+    protected Boolean historyExclude;
+    @XmlAttribute(name = "unique")
+    protected Boolean unique;
+    @XmlAttribute(name = "uniqueOneToOne")
+    protected Boolean uniqueOneToOne;
+    @XmlAttribute(name = "oldDefaultValue")
+    protected String oldDefaultValue;
+    @XmlAttribute(name = "newDefaultValue")
+    protected String newDefaultValue;
+    @XmlAttribute(name = "oldCheckConstraint")
+    protected String oldCheckConstraint;
+    @XmlAttribute(name = "newCheckConstraint")
+    protected String newCheckConstraint;
+    @XmlAttribute(name = "oldReferences")
+    protected String oldReferences;
+    @XmlAttribute(name = "newReferences")
+    protected String newReferences;
+
+    /**
+     * Gets the value of the columnName property.
+     * 
+     * @return
+     *     possible object is
+     *     {@link String }
+     *     
+     */
+    public String getColumnName() {
+        return columnName;
+    }
+
+    /**
+     * Sets the value of the columnName property.
+     * 
+     * @param value
+     *     allowed object is
+     *     {@link String }
+     *     
+     */
+    public void setColumnName(String value) {
+        this.columnName = value;
+    }
+
+    /**
+     * Gets the value of the tableName property.
+     * 
+     * @return
+     *     possible object is
+     *     {@link String }
+     *     
+     */
+    public String getTableName() {
+        return tableName;
+    }
+
+    /**
+     * Sets the value of the tableName property.
+     * 
+     * @param value
+     *     allowed object is
+     *     {@link String }
+     *     
+     */
+    public void setTableName(String value) {
+        this.tableName = value;
+    }
+
+    /**
+     * Gets the value of the type property.
+     * 
+     * @return
+     *     possible object is
+     *     {@link String }
+     *     
+     */
+    public String getType() {
+        return type;
+    }
+
+    /**
+     * Sets the value of the type property.
+     * 
+     * @param value
+     *     allowed object is
+     *     {@link String }
+     *     
+     */
+    public void setType(String value) {
+        this.type = value;
+    }
+
+    /**
+     * Gets the value of the notnull property.
+     * 
+     * @return
+     *     possible object is
+     *     {@link Boolean }
+     *     
+     */
+    public Boolean isNotnull() {
+        return notnull;
+    }
+
+    /**
+     * Sets the value of the notnull property.
+     * 
+     * @param value
+     *     allowed object is
+     *     {@link Boolean }
+     *     
+     */
+    public void setNotnull(Boolean value) {
+        this.notnull = value;
+    }
+
+    /**
+     * Gets the value of the historyExclude property.
+     * 
+     * @return
+     *     possible object is
+     *     {@link Boolean }
+     *     
+     */
+    public Boolean isHistoryExclude() {
+        return historyExclude;
+    }
+
+    /**
+     * Sets the value of the historyExclude property.
+     * 
+     * @param value
+     *     allowed object is
+     *     {@link Boolean }
+     *     
+     */
+    public void setHistoryExclude(Boolean value) {
+        this.historyExclude = value;
+    }
+
+    /**
+     * Gets the value of the unique property.
+     * 
+     * @return
+     *     possible object is
+     *     {@link Boolean }
+     *     
+     */
+    public Boolean isUnique() {
+        return unique;
+    }
+
+    /**
+     * Sets the value of the unique property.
+     * 
+     * @param value
+     *     allowed object is
+     *     {@link Boolean }
+     *     
+     */
+    public void setUnique(Boolean value) {
+        this.unique = value;
+    }
+
+    /**
+     * Gets the value of the uniqueOneToOne property.
+     * 
+     * @return
+     *     possible object is
+     *     {@link Boolean }
+     *     
+     */
+    public Boolean isUniqueOneToOne() {
+        return uniqueOneToOne;
+    }
+
+    /**
+     * Sets the value of the uniqueOneToOne property.
+     * 
+     * @param value
+     *     allowed object is
+     *     {@link Boolean }
+     *     
+     */
+    public void setUniqueOneToOne(Boolean value) {
+        this.uniqueOneToOne = value;
+    }
+
+    /**
+     * Gets the value of the oldDefaultValue property.
+     * 
+     * @return
+     *     possible object is
+     *     {@link String }
+     *     
+     */
+    public String getOldDefaultValue() {
+        return oldDefaultValue;
+    }
+
+    /**
+     * Sets the value of the oldDefaultValue property.
+     * 
+     * @param value
+     *     allowed object is
+     *     {@link String }
+     *     
+     */
+    public void setOldDefaultValue(String value) {
+        this.oldDefaultValue = value;
+    }
+
+    /**
+     * Gets the value of the newDefaultValue property.
+     * 
+     * @return
+     *     possible object is
+     *     {@link String }
+     *     
+     */
+    public String getNewDefaultValue() {
+        return newDefaultValue;
+    }
+
+    /**
+     * Sets the value of the newDefaultValue property.
+     * 
+     * @param value
+     *     allowed object is
+     *     {@link String }
+     *     
+     */
+    public void setNewDefaultValue(String value) {
+        this.newDefaultValue = value;
+    }
+
+    /**
+     * Gets the value of the oldCheckConstraint property.
+     * 
+     * @return
+     *     possible object is
+     *     {@link String }
+     *     
+     */
+    public String getOldCheckConstraint() {
+        return oldCheckConstraint;
+    }
+
+    /**
+     * Sets the value of the oldCheckConstraint property.
+     * 
+     * @param value
+     *     allowed object is
+     *     {@link String }
+     *     
+     */
+    public void setOldCheckConstraint(String value) {
+        this.oldCheckConstraint = value;
+    }
+
+    /**
+     * Gets the value of the newCheckConstraint property.
+     * 
+     * @return
+     *     possible object is
+     *     {@link String }
+     *     
+     */
+    public String getNewCheckConstraint() {
+        return newCheckConstraint;
+    }
+
+    /**
+     * Sets the value of the newCheckConstraint property.
+     * 
+     * @param value
+     *     allowed object is
+     *     {@link String }
+     *     
+     */
+    public void setNewCheckConstraint(String value) {
+        this.newCheckConstraint = value;
+    }
+
+    /**
+     * Gets the value of the oldReferences property.
+     * 
+     * @return
+     *     possible object is
+     *     {@link String }
+     *     
+     */
+    public String getOldReferences() {
+        return oldReferences;
+    }
+
+    /**
+     * Sets the value of the oldReferences property.
+     * 
+     * @param value
+     *     allowed object is
+     *     {@link String }
+     *     
+     */
+    public void setOldReferences(String value) {
+        this.oldReferences = value;
+    }
+
+    /**
+     * Gets the value of the newReferences property.
+     * 
+     * @return
+     *     possible object is
+     *     {@link String }
+     *     
+     */
+    public String getNewReferences() {
+        return newReferences;
+    }
+
+    /**
+     * Sets the value of the newReferences property.
+     * 
+     * @param value
+     *     allowed object is
+     *     {@link String }
+     *     
+     */
+    public void setNewReferences(String value) {
+        this.newReferences = value;
+    }
+
+}

src/main/java/com/avaje/ebean/dbmigration/migration/ChangeSet.java

@@ -51,14 +51,10 @@ public class ChangeSet {
         @XmlElement(name = "dropTable", type = DropTable.class),
         @XmlElement(name = "renameTable", type = RenameTable.class),
         @XmlElement(name = "createHistoryTable", type = CreateHistoryTable.class),
-        @XmlElement(name = "createView", type = CreateView.class),
-        @XmlElement(name = "dropView", type = DropView.class),
-        @XmlElement(name = "renameView", type = RenameView.class),
         @XmlElement(name = "addColumn", type = AddColumn.class),
         @XmlElement(name = "dropColumn", type = DropColumn.class),
-        @XmlElement(name = "renameColumn", type = RenameColumn.class),
-        @XmlElement(name = "addForeignKey", type = AddForeignKey.class),
-        @XmlElement(name = "dropForeignKey", type = DropForeignKey.class)
+        @XmlElement(name = "alterColumn", type = AlterColumn.class),
+        @XmlElement(name = "renameColumn", type = RenameColumn.class)
     })
     protected List<Object> changeSetChildren;
     @XmlAttribute(name = "type", required = true)
@@ -94,14 +90,10 @@ public class ChangeSet {
      * {@link DropTable }
      * {@link RenameTable }
      * {@link CreateHistoryTable }
-     * {@link CreateView }
-     * {@link DropView }
-     * {@link RenameView }
      * {@link AddColumn }
      * {@link DropColumn }
+     * {@link AlterColumn }
      * {@link RenameColumn }
-     * {@link AddForeignKey }
-     * {@link DropForeignKey }
      * 
      * 
      */

src/main/java/com/avaje/ebean/dbmigration/migration/Column.java

@@ -23,6 +23,7 @@ import javax.xml.bind.annotation.XmlValue;
  *       <attribute name="defaultValue" type="{http://www.w3.org/2001/XMLSchema}string" />
  *       <attribute name="notnull" type="{http://www.w3.org/2001/XMLSchema}boolean" />
  *       <attribute name="checkConstraint" type="{http://www.w3.org/2001/XMLSchema}string" />
+ *       <attribute name="historyExclude" type="{http://www.w3.org/2001/XMLSchema}boolean" />
  *       <attribute name="unique" type="{http://www.w3.org/2001/XMLSchema}boolean" />
  *       <attribute name="uniqueOneToOne" type="{http://www.w3.org/2001/XMLSchema}boolean" />
  *       <attribute name="primaryKey" type="{http://www.w3.org/2001/XMLSchema}boolean" />
@@ -55,6 +56,8 @@ public class Column {
     protected Boolean notnull;
     @XmlAttribute(name = "checkConstraint")
     protected String checkConstraint;
+    @XmlAttribute(name = "historyExclude")
+    protected Boolean historyExclude;
     @XmlAttribute(name = "unique")
     protected Boolean unique;
     @XmlAttribute(name = "uniqueOneToOne")
@@ -212,6 +215,30 @@ public class Column {
         this.checkConstraint = value;
     }
 
+    /**
+     * Gets the value of the historyExclude property.
+     * 
+     * @return
+     *     possible object is
+     *     {@link Boolean }
+     *     
+     */
+    public Boolean isHistoryExclude() {
+        return historyExclude;
+    }
+
+    /**
+     * Sets the value of the historyExclude property.
+     * 
+     * @param value
+     *     allowed object is
+     *     {@link Boolean }
+     *     
+     */
+    public void setHistoryExclude(Boolean value) {
+        this.historyExclude = value;
+    }
+
     /**
      * Gets the value of the unique property.
      * 

src/main/java/com/avaje/ebean/dbmigration/migration/ObjectFactory.java

@@ -30,11 +30,19 @@ public class ObjectFactory {
     }
 
     /**
-     * Create an instance of {@link CreateTable }
+     * Create an instance of {@link Rollback }
      * 
      */
-    public CreateTable createCreateTable() {
-        return new CreateTable();
+    public Rollback createRollback() {
+        return new Rollback();
+    }
+
+    /**
+     * Create an instance of {@link AddColumn }
+     * 
+     */
+    public AddColumn createAddColumn() {
+        return new AddColumn();
     }
 
     /**
@@ -45,6 +53,14 @@ public class ObjectFactory {
         return new Column();
     }
 
+    /**
+     * Create an instance of {@link CreateTable }
+     * 
+     */
+    public CreateTable createCreateTable() {
+        return new CreateTable();
+    }
+
     /**
      * Create an instance of {@link UniqueConstraint }
      * 
@@ -62,11 +78,11 @@ public class ObjectFactory {
     }
 
     /**
-     * Create an instance of {@link DropForeignKey }
+     * Create an instance of {@link Apply }
      * 
      */
-    public DropForeignKey createDropForeignKey() {
-        return new DropForeignKey();
+    public Apply createApply() {
+        return new Apply();
     }
 
     /**
@@ -101,6 +117,14 @@ public class ObjectFactory {
         return new DropHistoryTable();
     }
 
+    /**
+     * Create an instance of {@link AlterColumn }
+     * 
+     */
+    public AlterColumn createAlterColumn() {
+        return new AlterColumn();
+    }
+
     /**
      * Create an instance of {@link DropColumn }
      * 
@@ -110,11 +134,11 @@ public class ObjectFactory {
     }
 
     /**
-     * Create an instance of {@link DropView }
+     * Create an instance of {@link ChangeSet }
      * 
      */
-    public DropView createDropView() {
-        return new DropView();
+    public ChangeSet createChangeSet() {
+        return new ChangeSet();
     }
 
     /**
@@ -126,19 +150,11 @@ public class ObjectFactory {
     }
 
     /**
-     * Create an instance of {@link Apply }
+     * Create an instance of {@link DropTable }
      * 
      */
-    public Apply createApply() {
-        return new Apply();
-    }
-
-    /**
-     * Create an instance of {@link Rollback }
-     * 
-     */
-    public Rollback createRollback() {
-        return new Rollback();
+    public DropTable createDropTable() {
+        return new DropTable();
     }
 
     /**
@@ -157,62 +173,6 @@ public class ObjectFactory {
         return new RenameColumn();
     }
 
-    /**
-     * Create an instance of {@link CreateView }
-     * 
-     */
-    public CreateView createCreateView() {
-        return new CreateView();
-    }
-
-    /**
-     * Create an instance of {@link DropTable }
-     * 
-     */
-    public DropTable createDropTable() {
-        return new DropTable();
-    }
-
-    /**
-     * Create an instance of {@link AddColumn }
-     * 
-     */
-    public AddColumn createAddColumn() {
-        return new AddColumn();
-    }
-
-    /**
-     * Create an instance of {@link RenameView }
-     * 
-     */
-    public RenameView createRenameView() {
-        return new RenameView();
-    }
-
-    /**
-     * Create an instance of {@link AddForeignKey }
-     * 
-     */
-    public AddForeignKey createAddForeignKey() {
-        return new AddForeignKey();
-    }
-
-    /**
-     * Create an instance of {@link ChangeSet }
-     * 
-     */
-    public ChangeSet createChangeSet() {
-        return new ChangeSet();
-    }
-
-    /**
-     * Create an instance of {@link Application }
-     * 
-     */
-    public Application createApplication() {
-        return new Application();
-    }
-
     /**
      * Create an instance of {@link Migration }
      * 
@@ -221,12 +181,4 @@ public class ObjectFactory {
         return new Migration();
     }
 
-    /**
-     * Create an instance of {@link Applications }
-     * 
-     */
-    public Applications createApplications() {
-        return new Applications();
-    }
-
 }

src/main/java/com/avaje/ebean/dbmigration/migrationreader/MigrationXmlReader.java

@@ -15,6 +15,19 @@ public class MigrationXmlReader {
 
   private static final MigrationXmlReader INSTANCE = new MigrationXmlReader();
 
+  /**
+   * Read and return a Migration from an xml document at the given resource path.
+   */
+  public static Migration readMaybe(String resourcePath) {
+
+    InputStream is = MigrationXmlReader.class.getResourceAsStream(resourcePath);
+    if (is == null) {
+      return null;
+    }
+
+    return INSTANCE.read(is);
+  }
+
   /**
    * Read and return a Migration from an xml document at the given resource path.
    */

src/main/java/com/avaje/ebean/dbmigration/model/CurrentModel.java

@@ -2,7 +2,6 @@ package com.avaje.ebean.dbmigration.model;
 
 import com.avaje.ebean.dbmigration.ddlgeneration.DdlHandler;
 import com.avaje.ebean.dbmigration.ddlgeneration.DdlWrite;
-import com.avaje.ebean.dbmigration.ddlgeneration.platform.DdlNamingConvention;
 import com.avaje.ebean.dbmigration.migration.ChangeSet;
 import com.avaje.ebean.dbmigration.migration.Migration;
 import com.avaje.ebean.dbmigration.migrationreader.MigrationXmlWriter;
@@ -22,17 +21,22 @@ public class CurrentModel {
 
   private final SpiEbeanServer server;
 
-  private DdlNamingConvention namingConvention;
-
   private ModelContainer model;
+
   private ChangeSet changeSet;
+
   private DdlWrite write;
 
+  /**
+   * Construct with a given EbeanServer instance.
+   */
   public CurrentModel(SpiEbeanServer server) {
     this.server = server;
-    this.namingConvention = new DdlNamingConvention();
   }
 
+  /**
+   * Return the current model by reading all the bean descriptors and properties.
+   */
   public ModelContainer read() {
     if (model == null) {
       model = new ModelContainer();
@@ -48,6 +52,9 @@ public class CurrentModel {
    this.changeSet = changeSet;
   }
 
+  /**
+   * Return as a ChangeSet.
+   */
   public ChangeSet getChangeSet() {
     read();
     if (changeSet == null) {
@@ -56,6 +63,9 @@ public class CurrentModel {
     return changeSet;
   }
 
+  /**
+   * Write as migration xml to the given file.
+   */
   public void writeMigration(File file) {
 
     ChangeSet changeSet = getChangeSet();
@@ -66,6 +76,9 @@ public class CurrentModel {
     writer.write(migration, file);
   }
 
+  /**
+   * Return the 'Create' DDL.
+   */
   public String getCreateDdl() throws IOException {
 
     createDdl();
@@ -78,6 +91,9 @@ public class CurrentModel {
     return ddl.toString();
   }
 
+  /**
+   * Return the 'Drop' DDL.
+   */
   public String getDropDdl() throws IOException {
 
     createDdl();
@@ -89,16 +105,9 @@ public class CurrentModel {
     return ddl.toString();
   }
 
-  public DdlWrite generateDdl(ChangeSet changeSet) throws IOException {
-
-    DdlWrite write = new DdlWrite();
-
-    DdlHandler handler = handler();
-    handler.generate(write, changeSet);
-
-    return write;
-  }
-
+  /**
+   * Create all the DDL based on the changeSet.
+   */
   private void createDdl() throws IOException {
 
     if (write == null) {
@@ -111,8 +120,10 @@ public class CurrentModel {
     }
   }
 
+  /**
+   * Return the platform specific DdlHandler (to generate DDL).
+   */
   private DdlHandler handler() {
-
     return server.getDatabasePlatform().createDdlHandler();
   }
 

src/main/java/com/avaje/ebean/dbmigration/model/MColumn.java

@@ -1,5 +1,6 @@
 package com.avaje.ebean.dbmigration.model;
 
+import com.avaje.ebean.dbmigration.migration.AlterColumn;
 import com.avaje.ebean.dbmigration.migration.Column;
 
 /**
@@ -12,6 +13,7 @@ public class MColumn {
   private String checkConstraint;
   private String defaultValue;
   private String references;
+  private boolean historyExclude;
   private boolean notnull;
   private boolean primaryKey;
   private boolean identity;
@@ -34,6 +36,7 @@ public class MColumn {
     this.primaryKey = Boolean.TRUE.equals(column.isPrimaryKey());
     this.identity = Boolean.TRUE.equals(column.isIdentity());
     this.unique = Boolean.TRUE.equals(column.isUnique());
+    this.historyExclude = Boolean.TRUE.equals(column.isHistoryExclude());
   }
 
   public MColumn(String name, String type) {
@@ -103,6 +106,14 @@ public class MColumn {
     this.notnull = notnull;
   }
 
+  public boolean isHistoryExclude() {
+    return historyExclude;
+  }
+
+  public void setHistoryExclude(boolean historyExclude) {
+    this.historyExclude = historyExclude;
+  }
+
   public void setUnique(boolean unique) {
     this.unique = unique;
   }
@@ -136,6 +147,7 @@ public class MColumn {
     if (uniqueOneToOne) c.setUniqueOneToOne(true);
     if (primaryKey) c.setPrimaryKey(true);
     if (identity) c.setIdentity(true);
+    if (historyExclude) c.setHistoryExclude(true);
 
     c.setCheckConstraint(checkConstraint);
     c.setReferences(references);
@@ -143,4 +155,64 @@ public class MColumn {
 
     return c;
   }
+
+  private boolean different(String val1, String val2) {
+    return (val1 == null) ? val2 != null : !val1.equals(val2);
+  }
+
+  AlterColumn alterColumn;
+
+  private AlterColumn getAlterColumn(String tableName) {
+    if (alterColumn == null) {
+      alterColumn = new AlterColumn();
+      alterColumn.setColumnName(name);
+      alterColumn.setTableName(tableName);
+    }
+    return alterColumn;
+  }
+
+  public void compare(ModelDiff modelDiff, MTable table, MColumn newColumn) {
+
+    String tableName = table.getName();
+
+    this.alterColumn = null;
+
+    if (different(type, newColumn.type)) {
+      getAlterColumn(tableName).setType(newColumn.type);
+    }
+    if (historyExclude != newColumn.historyExclude) {
+      getAlterColumn(tableName).setHistoryExclude(newColumn.historyExclude);
+    }
+    if (notnull != newColumn.notnull) {
+      getAlterColumn(tableName).setNotnull(newColumn.notnull);
+    }
+    if (different(defaultValue, newColumn.defaultValue)) {
+      AlterColumn alter = getAlterColumn(tableName);
+      alter.setOldDefaultValue(defaultValue);
+      alter.setNewDefaultValue(newColumn.defaultValue);
+    }
+    if (different(checkConstraint, newColumn.checkConstraint)) {
+      AlterColumn alter = getAlterColumn(tableName);
+      alter.setOldCheckConstraint(checkConstraint);
+      alter.setNewCheckConstraint(newColumn.checkConstraint);
+    }
+    if (different(references, newColumn.references)) {
+      AlterColumn alter = getAlterColumn(tableName);
+      alter.setOldReferences(references);
+      alter.setNewReferences(newColumn.references);
+    }
+
+    if (unique != newColumn.unique) {
+      AlterColumn alter = getAlterColumn(tableName);
+      alter.setUnique(newColumn.unique);
+    }
+    if (uniqueOneToOne != newColumn.uniqueOneToOne) {
+      AlterColumn alter = getAlterColumn(tableName);
+      alter.setUniqueOneToOne(newColumn.uniqueOneToOne);
+    }
+
+    if (alterColumn != null) {
+      modelDiff.addAlterColumn(alterColumn);
+    }
+  }
 }

src/main/java/com/avaje/ebean/dbmigration/model/MTable.java

@@ -8,9 +8,12 @@ import com.avaje.ebean.dbmigration.migration.IdentityType;
 
 import java.math.BigInteger;
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.LinkedHashMap;
+import java.util.LinkedHashSet;
 import java.util.List;
 import java.util.Map;
+import java.util.Set;
 
 /**
  * Holds the logical model for a given Table and everything associated to it.
@@ -29,11 +32,6 @@ import java.util.Map;
  */
 public class MTable {
 
-  /**
-   * Flag set to indicate
-   */
-  private boolean matched;
-
   private final String name;
 
   private String comment;
@@ -60,6 +58,8 @@ public class MTable {
 
   private List<MCompoundForeignKey> compoundKeys = new ArrayList<MCompoundForeignKey>();
 
+  private AddColumn addColumn;
+
   /**
    * Construct for migration.
    */
@@ -110,12 +110,37 @@ public class MTable {
     return createTable;
   }
 
-  public boolean isMatched() {
-    return matched;
-  }
+  public void compare(ModelDiff modelDiff, MTable newTable) {
+
+    // TODO: compare indexes?
+    // TODO: compare primary key
+
+    addColumn = null;
+
+    Set<String> mappedColumns = new LinkedHashSet<String>();
+
+    Collection<MColumn> newColumns = newTable.getColumns().values();
+    for (MColumn newColumn : newColumns) {
+      MColumn localColumn = columns.get(newColumn.getName());
+      if (localColumn == null) {
+        diffNewColumn(newColumn);
+      } else {
+        localColumn.compare(modelDiff, this, newColumn);
+        mappedColumns.add(newColumn.getName());
+      }
+    }
+
+    Collection<MColumn> existingColumns = columns.values();
+    for (MColumn existingColumn : existingColumns) {
+      if (!mappedColumns.contains(existingColumn.getName())) {
+        diffDropColumn(modelDiff, existingColumn);
+      }
+    }
+
+    if (addColumn != null) {
+      modelDiff.addAddColumn(addColumn);
+    }
 
-  public void setMatched(boolean matched) {
-    this.matched = matched;
   }
 
   /**
@@ -293,4 +318,24 @@ public class MTable {
     addColumn(newCol);
     return newCol;
   }
+
+
+  private void diffNewColumn(MColumn newColumn) {
+
+    if (addColumn == null) {
+      addColumn = new AddColumn();
+      addColumn.setTableName(name);
+    }
+
+    addColumn.getColumn().add(newColumn.createColumn());
+  }
+
+  private void diffDropColumn(ModelDiff modelDiff, MColumn existingColumn) {
+
+    DropColumn dropColumn = new DropColumn();
+    dropColumn.setTableName(name);
+    dropColumn.setColumnName(existingColumn.getName());
+
+    modelDiff.addDropColumn(dropColumn);
+  }
 }

src/main/java/com/avaje/ebean/dbmigration/model/MigrationModel.java

@@ -0,0 +1,93 @@
+package com.avaje.ebean.dbmigration.model;
+
+import com.avaje.ebean.dbmigration.migration.Migration;
+import com.avaje.ebean.dbmigration.migrationreader.MigrationXmlReader;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.LinkedHashSet;
+import java.util.Set;
+
+/**
+ * Build the model from the series of migrations.
+ */
+public class MigrationModel {
+
+  private static final Logger logger = LoggerFactory.getLogger(MigrationModel.class);
+
+  private final ModelContainer model = new ModelContainer();
+
+  private final Set<String> readVersions = new LinkedHashSet<String>();
+
+  private final String resourcePath;
+
+  public MigrationModel(String resourcePath) {
+    this.resourcePath = normaliseResourcePath(resourcePath);
+  }
+
+  private String normaliseResourcePath(String resourcePath) {
+    if (resourcePath.endsWith("/")) {
+      // trim trailing slash
+      resourcePath = resourcePath.substring(0, resourcePath.length()-1);
+    }
+    if (resourcePath.startsWith("/")) {
+      // trim leading slash
+      resourcePath = resourcePath.substring(1);
+    }
+    return resourcePath;
+  }
+
+  /**
+   * Read all the migrations returning the model with all
+   * the migrations applied in version order.
+   */
+  public ModelContainer read() {
+
+    readMigrations();
+    logger.info("read versions {}", readVersions);
+    return model;
+  }
+
+  /**
+   * Return the set of versions that were read.
+   */
+  public Set<String> getReadVersions() {
+    return readVersions;
+  }
+
+  private void readMigrations() {
+    for (int majorVersion = 1; majorVersion < 100; majorVersion++) {
+      if (!readMinorVersions(majorVersion)){
+        // no major.0 version so stopping
+        return;
+      }
+    }
+  }
+
+  private boolean readMinorVersions(int majorVersion) {
+
+    for (int minorVersion = 0; minorVersion < 100; minorVersion++) {
+      if (!readMigration(majorVersion, minorVersion)) {
+        // continue reading next major if minorVersion 0 was read
+        return (minorVersion > 0);
+      }
+    }
+    return true;
+  }
+
+  private boolean readMigration(int majorVersion, int minorVersion) {
+
+    String version = majorVersion+"."+minorVersion;
+    String path = "/"+resourcePath+"/v"+version+".xml";
+
+    Migration migration = MigrationXmlReader.readMaybe(path);
+    if (migration == null) {
+      return false;
+    }
+    readVersions.add(version);
+    logger.trace("... read migration v{}", version);
+    model.apply(migration);
+    return true;
+  }
+
+}

src/main/java/com/avaje/ebean/dbmigration/model/ModelContainer.java

@@ -23,6 +23,9 @@ public class ModelContainer {
    */
   private Map<String, MTable> tables = new LinkedHashMap<String, MTable>();
 
+  public ModelContainer() {
+
+  }
 
   /**
    * Return the map of all the tables.
@@ -73,7 +76,7 @@ public class ModelContainer {
   protected void applyChange(CreateTable createTable) {
     String tableName = createTable.getName();
     if (tables.containsKey(tableName)) {
-      throw new IllegalStateException("Table [" + tableName + "] already exists?");
+      throw new IllegalStateException("Table [" + tableName + "] already exists in model?");
     }
     MTable table = new MTable(createTable);
     tables.put(tableName, table);
@@ -85,7 +88,7 @@ public class ModelContainer {
   protected void applyChange(AddColumn addColumn) {
     MTable table = tables.get(addColumn.getTableName());
     if (table == null) {
-      throw new IllegalStateException("Table [" + addColumn.getTableName() + "] does not exist?");
+      throw new IllegalStateException("Table [" + addColumn.getTableName() + "] does not exist in model?");
     }
     table.apply(addColumn);
   }
@@ -96,7 +99,7 @@ public class ModelContainer {
   protected void applyChange(DropColumn dropColumn) {
     MTable table = tables.get(dropColumn.getTableName());
     if (table == null) {
-      throw new IllegalStateException("Table [" + dropColumn.getTableName() + "] does not exist?");
+      throw new IllegalStateException("Table [" + dropColumn.getTableName() + "] does not exist in model?");
     }
     table.apply(dropColumn);
   }

src/main/java/com/avaje/ebean/dbmigration/model/ModelDiff.java

@@ -1,5 +1,9 @@
 package com.avaje.ebean.dbmigration.model;
 
+import com.avaje.ebean.dbmigration.migration.AddColumn;
+import com.avaje.ebean.dbmigration.migration.AlterColumn;
+import com.avaje.ebean.dbmigration.migration.DropColumn;
+
 import java.util.ArrayList;
 import java.util.List;
 
@@ -12,17 +16,17 @@ public class ModelDiff {
   /**
    * The base model to which we compare the newer model.
    */
-  protected final ModelContainer baseModel;
+  private final ModelContainer baseModel;
 
   /**
    * List of 'create' type changes.
    */
-  protected final List<Object> createChanges = new ArrayList<Object>();
+  private final List<Object> createChanges = new ArrayList<Object>();
 
   /**
-   * List of 'drop' type changes. Potential for putting into a separate changeSet.
+   * List of 'drop' type changes. Expected to be placed into a separate DDL script.
    */
-  protected final List<Object> dropChanges = new ArrayList<Object>();
+  private final List<Object> dropChanges = new ArrayList<Object>();
 
   /**
    * Construct with a base model.
@@ -77,7 +81,6 @@ public class ModelDiff {
   protected void addNewTable(MTable newTable) {
 
     createChanges.add(newTable.createTable());
-//    createChanges.add(newTable.createForeignKeys());
   }
 
   /**
@@ -85,14 +88,19 @@ public class ModelDiff {
    */
   protected void compareTables(MTable currentTable, MTable newTable) {
 
-    //TODO: compareTables()
-    // changed columns
-    // find additional columns
-    // find removed columns
-    // changes to indexes?
-    // changes to primary key
-    // changes to foreign key
-    // changes to unique constraints?
+    currentTable.compare(this, newTable);
 
   }
+
+  public void addAlterColumn(AlterColumn alterColumn) {
+    createChanges.add(alterColumn);
+  }
+
+  public void addDropColumn(DropColumn dropColumn) {
+    dropChanges.add(dropColumn);
+  }
+
+  public void addAddColumn(AddColumn addColumn) {
+    createChanges.add(addColumn);
+  }
 }

src/main/java/com/avaje/ebeaninternal/server/core/DatabasePlatformFactory.java

@@ -9,6 +9,7 @@ import javax.sql.DataSource;
 
 import com.avaje.ebean.config.ServerConfig;
 import com.avaje.ebean.config.dbplatform.*;
+import com.avaje.ebean.dbmigration.DbOffline;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -30,11 +31,17 @@ public class DatabasePlatformFactory {
 
     try {
 
+      String offlinePlatform = DbOffline.getPlatform();
+      if (offlinePlatform != null) {
+        logger.info("offline platform [{}]", offlinePlatform);
+        return byDatabaseName(offlinePlatform);
+      }
+
       if (serverConfig.getDatabasePlatformName() != null) {
         // choose based on dbName
         return byDatabaseName(serverConfig.getDatabasePlatformName());
-
       }
+
       if (serverConfig.getDataSourceConfig().isOffline()) {
         String m = "You must specify a DatabasePlatformName when you are offline";
         throw new PersistenceException(m);

src/main/java/com/avaje/ebeaninternal/server/core/DefaultContainer.java

@@ -11,6 +11,7 @@ import com.avaje.ebean.config.PropertyMap;
 import com.avaje.ebean.config.ServerConfig;
 import com.avaje.ebean.config.UnderscoreNamingConvention;
 import com.avaje.ebean.config.dbplatform.DatabasePlatform;
+import com.avaje.ebean.dbmigration.DbOffline;
 import com.avaje.ebeaninternal.api.SpiBackgroundExecutor;
 import com.avaje.ebeaninternal.api.SpiEbeanServer;
 import com.avaje.ebeaninternal.server.cache.DefaultServerCacheFactory;
@@ -113,9 +114,6 @@ public class DefaultContainer implements SpiContainer {
         serverConfig.getDatabasePlatform().setDbEncrypt(serverConfig.getDbEncrypt());
       }
 
-      DatabasePlatform dbPlatform = serverConfig.getDatabasePlatform();
-
-
       // inform the NamingConvention of the associated DatabasePlaform
       serverConfig.getNamingConvention().setDatabasePlatform(serverConfig.getDatabasePlatform());
 
@@ -169,6 +167,7 @@ public class DefaultContainer implements SpiContainer {
 
       // start any services after registering with clusterManager
       server.start();
+      DbOffline.reset();
       return server;
     }
   }
@@ -284,6 +283,11 @@ public class DefaultContainer implements SpiContainer {
 
   private DataSource getDataSourceFromConfig(ServerConfig config) {
 
+    if (DbOffline.isSet()) {
+      logger.trace("... DbOffline using platform [{}]", DbOffline.getPlatform());
+      return null;
+    }
+
     DataSource ds;
 
     if (config.getDataSourceJndiName() != null) {
@@ -324,6 +328,10 @@ public class DefaultContainer implements SpiContainer {
    */
   private boolean checkDataSource(ServerConfig serverConfig) {
 
+    if (DbOffline.isSet()) {
+      return false;
+    }
+
     if (serverConfig.getDataSource() == null) {
       if (serverConfig.getDataSourceConfig().isOffline()) {
         // this is ok - offline DDL generation etc

src/main/java/com/avaje/ebeaninternal/server/type/ConvertInetAddresses.java

@@ -185,7 +185,6 @@ public final class ConvertInetAddresses {
     boolean isIpv6 = false;
 
     // handle IPv6 forms of IPv4 addresses
-    // TODO: use Ascii.toUpperCase() when available
     if (ipString.toUpperCase(Locale.US).startsWith("::FFFF:")) {
       ipString = ipString.substring(7);
     } else if (ipString.startsWith("::")) {

src/main/resources/ebean-dbmigration-1.0.xsd

@@ -8,20 +8,20 @@
   <!-- =========================================================== -->
 
   <!-- Root level type : applications -->
-  <xsd:element name="applications">
-    <xsd:complexType>
-      <xsd:sequence>
-        <xsd:element ref="application" minOccurs="0" maxOccurs="unbounded"/>
-      </xsd:sequence>
-    </xsd:complexType>
-  </xsd:element>
+  <!--<xsd:element name="applications">-->
+    <!--<xsd:complexType>-->
+      <!--<xsd:sequence>-->
+        <!--<xsd:element ref="application" minOccurs="0" maxOccurs="unbounded"/>-->
+      <!--</xsd:sequence>-->
+    <!--</xsd:complexType>-->
+  <!--</xsd:element>-->
 
-  <xsd:element name="application">
-    <xsd:complexType>
-      <xsd:attribute name="name" type="xsd:string" use="required"/>
-      <xsd:attribute name="resourcePath" type="xsd:string" use="required"/>
-    </xsd:complexType>
-  </xsd:element>
+  <!--<xsd:element name="application">-->
+    <!--<xsd:complexType>-->
+      <!--<xsd:attribute name="name" type="xsd:string" use="required"/>-->
+      <!--<xsd:attribute name="resourcePath" type="xsd:string" use="required"/>-->
+    <!--</xsd:complexType>-->
+  <!--</xsd:element>-->
 
 
   <!-- =========================================================== -->
@@ -201,6 +201,24 @@
     </xsd:complexType>
   </xsd:element>
 
+  <xsd:element name="alterColumn">
+    <xsd:complexType>
+      <xsd:attribute name="columnName" type="xsd:string" use="required"/>
+      <xsd:attribute name="tableName" type="xsd:string" use="required"/>
+      <xsd:attribute name="type" type="xsd:string"/>
+      <xsd:attribute name="notnull" type="xsd:boolean"/>
+      <xsd:attribute name="historyExclude" type="xsd:boolean"/>
+      <xsd:attribute name="unique" type="xsd:boolean"/>
+      <xsd:attribute name="uniqueOneToOne" type="xsd:boolean"/>
+      <xsd:attribute name="oldDefaultValue" type="xsd:string"/>
+      <xsd:attribute name="newDefaultValue" type="xsd:string"/>
+      <xsd:attribute name="oldCheckConstraint" type="xsd:string"/>
+      <xsd:attribute name="newCheckConstraint" type="xsd:string"/>
+      <xsd:attribute name="oldReferences" type="xsd:string"/>
+      <xsd:attribute name="newReferences" type="xsd:string"/>
+    </xsd:complexType>
+  </xsd:element>
+
   <xsd:element name="renameColumn">
     <xsd:complexType>
       <xsd:attribute name="oldName" type="xsd:string" use="required"/>
@@ -212,49 +230,49 @@
 
   <!-- VIEW  -->
 
-  <xsd:element name="createView">
-    <xsd:complexType>
-      <xsd:simpleContent>
-        <xsd:extension base="xsd:string">
-          <xsd:attribute name="name" type="xsd:string" use="required"/>
-          <xsd:attribute name="replaceIfExists" type="xsd:boolean"/>
-        </xsd:extension>
-      </xsd:simpleContent>
-    </xsd:complexType>
-  </xsd:element>
+  <!--<xsd:element name="createView">-->
+    <!--<xsd:complexType>-->
+      <!--<xsd:simpleContent>-->
+        <!--<xsd:extension base="xsd:string">-->
+          <!--<xsd:attribute name="name" type="xsd:string" use="required"/>-->
+          <!--<xsd:attribute name="replaceIfExists" type="xsd:boolean"/>-->
+        <!--</xsd:extension>-->
+      <!--</xsd:simpleContent>-->
+    <!--</xsd:complexType>-->
+  <!--</xsd:element>-->
 
-  <xsd:element name="dropView">
-    <xsd:complexType>
-      <xsd:attribute name="name" type="xsd:string" use="required"/>
-    </xsd:complexType>
-  </xsd:element>
+  <!--<xsd:element name="dropView">-->
+    <!--<xsd:complexType>-->
+      <!--<xsd:attribute name="name" type="xsd:string" use="required"/>-->
+    <!--</xsd:complexType>-->
+  <!--</xsd:element>-->
 
-  <xsd:element name="renameView">
-    <xsd:complexType>
-      <xsd:attribute name="oldName" type="xsd:string" use="required"/>
-      <xsd:attribute name="newName" type="xsd:string" use="required"/>
-    </xsd:complexType>
-  </xsd:element>
+  <!--<xsd:element name="renameView">-->
+    <!--<xsd:complexType>-->
+      <!--<xsd:attribute name="oldName" type="xsd:string" use="required"/>-->
+      <!--<xsd:attribute name="newName" type="xsd:string" use="required"/>-->
+    <!--</xsd:complexType>-->
+  <!--</xsd:element>-->
 
   <!-- FOREIGN KEY -->
 
-  <xsd:element name="addForeignKey">
-    <xsd:complexType>
-      <xsd:simpleContent>
-        <xsd:extension base="xsd:string">
-          <xsd:attribute name="name" type="xsd:string" use="required"/>
-          <xsd:attribute name="columns" type="xsd:string" use="required"/>
-          <xsd:attribute name="references" type="xsd:string" use="required"/>
-        </xsd:extension>
-      </xsd:simpleContent>
-    </xsd:complexType>
-  </xsd:element>
+  <!--<xsd:element name="addForeignKey">-->
+    <!--<xsd:complexType>-->
+      <!--<xsd:simpleContent>-->
+        <!--<xsd:extension base="xsd:string">-->
+          <!--<xsd:attribute name="name" type="xsd:string" use="required"/>-->
+          <!--<xsd:attribute name="columns" type="xsd:string" use="required"/>-->
+          <!--<xsd:attribute name="references" type="xsd:string" use="required"/>-->
+        <!--</xsd:extension>-->
+      <!--</xsd:simpleContent>-->
+    <!--</xsd:complexType>-->
+  <!--</xsd:element>-->
 
-  <xsd:element name="dropForeignKey">
-    <xsd:complexType mixed="true">
-      <xsd:attribute name="name" type="xsd:string" use="required"/>
-    </xsd:complexType>
-  </xsd:element>
+  <!--<xsd:element name="dropForeignKey">-->
+    <!--<xsd:complexType mixed="true">-->
+      <!--<xsd:attribute name="name" type="xsd:string" use="required"/>-->
+    <!--</xsd:complexType>-->
+  <!--</xsd:element>-->
 
   <!-- ============================================ -->
 
@@ -263,13 +281,13 @@
       <xsd:attribute name="name" type="xsd:string" use="required"/>
       <xsd:attribute name="type" type="xsd:string" use="required"/>
       <xsd:attribute name="defaultValue" type="xsd:string"/>
-      <!--<xsd:attributeGroup ref="columnAttributes"/>-->
       <xsd:attribute name="notnull" type="xsd:boolean"/>
       <xsd:attribute name="checkConstraint" type="xsd:string"/>
+      <xsd:attribute name="historyExclude" type="xsd:boolean"/>
       <xsd:attribute name="unique" type="xsd:boolean"/>
       <xsd:attribute name="uniqueOneToOne" type="xsd:boolean"/>
       <xsd:attribute name="primaryKey" type="xsd:boolean"/>
-      <xsd:attribute name="identity" type="xsd:boolean"/> <!-- aka autoincrement/identity -->
+      <xsd:attribute name="identity" type="xsd:boolean"/>
       <xsd:attribute name="references" type="xsd:string"/>
       <xsd:attribute name="comment" type="xsd:string"/>
     </xsd:complexType>
@@ -285,7 +303,6 @@
   <xsd:group name="changeSetChildren">
     <xsd:choice>
       <xsd:element ref="configuration" maxOccurs="1"/>
-
       <xsd:element ref="sql" maxOccurs="unbounded"/>
 
       <xsd:element ref="createTable" maxOccurs="unbounded"/>
@@ -294,16 +311,17 @@
 
       <xsd:element ref="createHistoryTable" maxOccurs="unbounded"/>
 
-      <xsd:element ref="createView" maxOccurs="unbounded"/>
-      <xsd:element ref="dropView" maxOccurs="unbounded"/>
-      <xsd:element ref="renameView" maxOccurs="unbounded"/>
-
       <xsd:element ref="addColumn" maxOccurs="unbounded"/>
       <xsd:element ref="dropColumn" maxOccurs="unbounded"/>
+      <xsd:element ref="alterColumn" maxOccurs="unbounded"/>
       <xsd:element ref="renameColumn" maxOccurs="unbounded"/>
 
-      <xsd:element ref="addForeignKey" maxOccurs="unbounded"/>
-      <xsd:element ref="dropForeignKey" maxOccurs="unbounded"/>
+      <!--<xsd:element ref="createView" maxOccurs="unbounded"/>-->
+      <!--<xsd:element ref="dropView" maxOccurs="unbounded"/>-->
+      <!--<xsd:element ref="renameView" maxOccurs="unbounded"/>-->
+
+      <!--<xsd:element ref="addForeignKey" maxOccurs="unbounded"/>-->
+      <!--<xsd:element ref="dropForeignKey" maxOccurs="unbounded"/>-->
 
       <!--<xsd:element ref="createIndex" maxOccurs="unbounded"/>-->
       <!--<xsd:element ref="dropIndex" maxOccurs="unbounded"/>-->
@@ -312,23 +330,13 @@
       <!--<xsd:element ref="alterSequence" maxOccurs="unbounded"/>-->
       <!--<xsd:element ref="dropSequence" maxOccurs="unbounded"/>-->
 
-      <!--<xsd:element ref="addNotNullConstraint" maxOccurs="unbounded"/>-->
-      <!--<xsd:element ref="dropNotNullConstraint" maxOccurs="unbounded"/>-->
-
       <!--<xsd:element ref="addPrimaryKey" maxOccurs="unbounded"/>-->
       <!--<xsd:element ref="dropPrimaryKey" maxOccurs="unbounded"/>-->
 
       <!--<xsd:element ref="addUniqueConstraint" maxOccurs="unbounded"/>-->
       <!--<xsd:element ref="dropUniqueConstraint" maxOccurs="unbounded"/>-->
 
-      <!--<xsd:element ref="addDefaultValue" maxOccurs="unbounded"/>-->
-      <!--<xsd:element ref="dropDefaultValue" maxOccurs="unbounded"/>-->
-
-      <!--<xsd:element ref="sql" maxOccurs="unbounded"/>-->
-      <!--<xsd:element ref="createProcedure" maxOccurs="unbounded"/>-->
-
     </xsd:choice>
   </xsd:group>
 
-
 </xsd:schema>

src/test/java/com/avaje/ebean/config/DbMigrationConfigTest.java

@@ -0,0 +1,23 @@
+package com.avaje.ebean.config;
+
+import org.junit.Test;
+
+import static org.assertj.core.api.Assertions.*;
+
+
+public class DbMigrationConfigTest {
+
+
+  @Test
+  public void testLoad() {
+
+    ServerConfig config = new ServerConfig();
+    config.setName("h2other");
+    config.loadFromProperties();
+
+    DbMigrationConfig migrationConfig = config.getMigrationConfig();
+
+    assertThat(migrationConfig.getAppName()).isEqualTo("myapp");
+    assertThat(migrationConfig.getResourcePath()).isEqualTo("dbmigration/myapp");
+  }
+}

src/test/java/com/avaje/ebean/dbmigration/DbMigrationTest.java

@@ -0,0 +1,32 @@
+package com.avaje.ebean.dbmigration;
+
+import com.avaje.ebean.BaseTestCase;
+import org.junit.Ignore;
+import org.junit.Test;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import static org.assertj.core.api.Assertions.*;
+
+public class DbMigrationTest extends BaseTestCase {
+
+  private static final Logger logger = LoggerFactory.getLogger(DbMigrationTest.class);
+
+  //@Ignore
+  @Test
+  public void writeCurrent() {
+
+    logger.info("start");
+
+    DbOffline.asH2();
+    DbMigration migration = new DbMigration();
+    DbOffline.reset();
+
+    migration.writeCurrent();
+
+    assertThat(DbOffline.isSet()).isFalse();
+
+    logger.info("end");
+  }
+
+}

src/test/java/com/avaje/ebean/dbmigration/migrationreader/MigrationXmlWriterTest.java

@@ -12,7 +12,7 @@ public class MigrationXmlWriterTest {
   Logger logger = LoggerFactory.getLogger(MigrationXmlWriterTest.class);
 
   @Test
-  public void testWrite() throws Exception {
+  public void testReadWrite() throws Exception {
 
     Migration migration = MigrationXmlReader.read("/container/test-create-table.xml");
 

src/test/java/com/avaje/ebean/dbmigration/model/MColumnTest.java

@@ -0,0 +1,273 @@
+package com.avaje.ebean.dbmigration.model;
+
+import com.avaje.ebean.dbmigration.migration.AlterColumn;
+import org.jetbrains.annotations.NotNull;
+import org.junit.Test;
+
+import static org.assertj.core.api.Assertions.*;
+
+
+public class MColumnTest {
+
+  MTable table = new MTable("tab");
+
+  MColumn basic() {
+    return new MColumn("col", "integer");
+  }
+
+  ModelDiff diff() {
+    return new ModelDiff();
+  }
+
+  @Test
+  public void noDiff() throws Exception {
+
+    ModelDiff diff = diff();
+    basic().compare(diff, table, basic());
+
+    assertThat(diff.getCreateChanges()).isEmpty();
+    assertThat(diff.getDropChanges()).isEmpty();
+  }
+
+  @Test
+  public void diffType() throws Exception {
+
+    ModelDiff diff = diff();
+    basic().compare(diff, table, new MColumn("col", "integer(8)"));
+
+    assertChanges(diff);
+    AlterColumn alterColumn = getAlterColumn(diff);
+    assertThat(alterColumn.getType()).isEqualTo("integer(8)");
+  }
+
+  @Test
+  public void diffNotNull() throws Exception {
+
+    ModelDiff diff = diff();
+    MColumn newCol = basic();
+    newCol.setNotnull(true);
+    basic().compare(diff, table, newCol);
+
+    assertChanges(diff);
+    AlterColumn alterColumn = getAlterColumn(diff);
+    assertThat(alterColumn.isNotnull()).isEqualTo(true);
+
+    assertThat(alterColumn.getType()).isNull();
+    assertThat(alterColumn.isUnique()).isNull();
+    assertThat(alterColumn.isUniqueOneToOne()).isNull();
+    assertThat(alterColumn.getNewDefaultValue()).isNull();
+  }
+
+  @Test
+  public void diffCheckAdd() throws Exception {
+
+    ModelDiff diff = diff();
+    MColumn newCol = basic();
+    newCol.setCheckConstraint("abc");
+    basic().compare(diff, table, newCol);
+
+    assertChanges(diff);
+    assertThat(getAlterColumn(diff).getNewCheckConstraint()).isEqualTo("abc");
+    assertThat(getAlterColumn(diff).getOldCheckConstraint()).isNull();
+  }
+
+  @Test
+  public void diffCheckRemove() throws Exception {
+
+    ModelDiff diff = diff();
+    MColumn newCol = basic();
+    MColumn oldCol = basic();
+    oldCol.setCheckConstraint("abc");
+    oldCol.compare(diff, table, newCol);
+
+    assertChanges(diff);
+    assertThat(getAlterColumn(diff).getNewCheckConstraint()).isNull();
+    assertThat(getAlterColumn(diff).getOldCheckConstraint()).isEqualTo("abc");
+  }
+
+  @Test
+  public void diffCheckChange() throws Exception {
+
+    ModelDiff diff = diff();
+    MColumn newCol = basic();
+    newCol.setCheckConstraint("abc");
+    MColumn oldCol = basic();
+    oldCol.setCheckConstraint("d");
+    oldCol.compare(diff, table, newCol);
+
+    assertChanges(diff);
+    assertThat(getAlterColumn(diff).getNewCheckConstraint()).isEqualTo("abc");
+    assertThat(getAlterColumn(diff).getOldCheckConstraint()).isEqualTo("d");
+  }
+
+  @Test
+  public void diffDefaultValueAdd() throws Exception {
+
+    ModelDiff diff = diff();
+    MColumn newCol = basic();
+    newCol.setDefaultValue("abc");
+    basic().compare(diff, table, newCol);
+
+    assertChanges(diff);
+    assertThat(getAlterColumn(diff).getNewDefaultValue()).isEqualTo("abc");
+    assertThat(getAlterColumn(diff).getOldDefaultValue()).isNull();
+  }
+
+  @Test
+  public void diffDefaultValueRemove() throws Exception {
+
+    ModelDiff diff = diff();
+    MColumn newCol = basic();
+    MColumn oldCol = basic();
+    oldCol.setDefaultValue("abc");
+    oldCol.compare(diff, table, newCol);
+
+    assertChanges(diff);
+    assertThat(getAlterColumn(diff).getNewDefaultValue()).isNull();
+    assertThat(getAlterColumn(diff).getOldDefaultValue()).isEqualTo("abc");
+  }
+
+  @Test
+  public void diffDefaultValueChange() throws Exception {
+
+    ModelDiff diff = diff();
+    MColumn newCol = basic();
+    newCol.setDefaultValue("abc");
+    MColumn oldCol = basic();
+    oldCol.setDefaultValue("d");
+    oldCol.compare(diff, table, newCol);
+
+    assertChanges(diff);
+    assertThat(getAlterColumn(diff).getNewDefaultValue()).isEqualTo("abc");
+    assertThat(getAlterColumn(diff).getOldDefaultValue()).isEqualTo("d");
+  }
+
+  @Test
+  public void diffReferencesAdd() throws Exception {
+
+    ModelDiff diff = diff();
+    MColumn newCol = basic();
+    newCol.setReferences("abc");
+    basic().compare(diff, table, newCol);
+
+    assertChanges(diff);
+    assertThat(getAlterColumn(diff).getNewReferences()).isEqualTo("abc");
+    assertThat(getAlterColumn(diff).getOldReferences()).isNull();
+  }
+
+
+  @Test
+  public void diffReferencesRemove() throws Exception {
+
+    ModelDiff diff = diff();
+    MColumn newCol = basic();
+    MColumn oldCol = basic();
+    oldCol.setReferences("abc");
+    oldCol.compare(diff, table, newCol);
+
+    assertChanges(diff);
+    assertThat(getAlterColumn(diff).getNewReferences()).isNull();
+    assertThat(getAlterColumn(diff).getOldReferences()).isEqualTo("abc");
+  }
+
+  @Test
+  public void diffReferencesChange() throws Exception {
+
+    ModelDiff diff = diff();
+    MColumn newCol = basic();
+    newCol.setReferences("abc");
+    MColumn oldCol = basic();
+    oldCol.setReferences("d");
+    oldCol.compare(diff, table, newCol);
+
+    assertChanges(diff);
+    assertThat(getAlterColumn(diff).getNewReferences()).isEqualTo("abc");
+    assertThat(getAlterColumn(diff).getOldReferences()).isEqualTo("d");
+  }
+
+  @Test
+  public void diffUniqueAdd() throws Exception {
+
+    ModelDiff diff = diff();
+    MColumn newCol = basic();
+    newCol.setUnique(true);
+    basic().compare(diff, table, newCol);
+
+    assertChanges(diff);
+    assertThat(getAlterColumn(diff).isUnique()).isEqualTo(true);
+  }
+
+  @Test
+  public void diffUniqueRemove() throws Exception {
+
+    ModelDiff diff = diff();
+    MColumn newCol = basic();
+    MColumn oldCol = basic();
+    oldCol.setUnique(true);
+    oldCol.compare(diff, table, newCol);
+
+    assertChanges(diff);
+    assertThat(getAlterColumn(diff).isUnique()).isEqualTo(false);
+  }
+
+  @Test
+  public void diffUniqueOneToOneAdd() throws Exception {
+
+    ModelDiff diff = diff();
+    MColumn newCol = basic();
+    newCol.setUniqueOneToOne(true);
+    basic().compare(diff, table, newCol);
+
+    assertChanges(diff);
+    assertThat(getAlterColumn(diff).isUniqueOneToOne()).isEqualTo(true);
+  }
+
+  @Test
+  public void diffUniqueOneToOneRemove() throws Exception {
+
+    ModelDiff diff = diff();
+    MColumn newCol = basic();
+    MColumn oldCol = basic();
+    oldCol.setUniqueOneToOne(true);
+    oldCol.compare(diff, table, newCol);
+
+    assertChanges(diff);
+    assertThat(getAlterColumn(diff).isUniqueOneToOne()).isEqualTo(false);
+  }
+
+  @Test
+  public void diffHistoryExcludeAdd() throws Exception {
+
+    ModelDiff diff = diff();
+    MColumn newCol = basic();
+    newCol.setHistoryExclude(true);
+    basic().compare(diff, table, newCol);
+
+    assertChanges(diff);
+    assertThat(getAlterColumn(diff).isHistoryExclude()).isEqualTo(true);
+  }
+
+  @Test
+  public void diffHistoryExcludeRemove() throws Exception {
+
+    ModelDiff diff = diff();
+    MColumn newCol = basic();
+    MColumn oldCol = basic();
+    oldCol.setHistoryExclude(true);
+    oldCol.compare(diff, table, newCol);
+
+    assertChanges(diff);
+    assertThat(getAlterColumn(diff).isHistoryExclude()).isEqualTo(false);
+  }
+
+  @NotNull
+  private AlterColumn getAlterColumn(ModelDiff diff) {
+    return (AlterColumn) diff.getCreateChanges().get(0);
+  }
+
+  private void assertChanges(ModelDiff diff) {
+    assertThat(diff.getDropChanges()).isEmpty();
+    assertThat(diff.getCreateChanges()).hasSize(1);
+  }
+
+}

src/test/java/com/avaje/ebean/dbmigration/model/MTableTest.java

@@ -0,0 +1,110 @@
+package com.avaje.ebean.dbmigration.model;
+
+import com.avaje.ebean.dbmigration.migration.AddColumn;
+import com.avaje.ebean.dbmigration.migration.AlterColumn;
+import com.avaje.ebean.dbmigration.migration.DropColumn;
+import org.junit.Test;
+
+import java.util.List;
+
+import static org.assertj.core.api.Assertions.*;
+
+public class MTableTest {
+
+  MTable base() {
+    MTable table = new MTable("tab");
+    table.addColumn(new MColumn("id","bigint"));
+    table.addColumn(new MColumn("name","varchar(20)"));
+    table.addColumn(new MColumn("status","varchar(3)"));
+
+    return table;
+  }
+
+  MTable newTable() {
+    MTable table = new MTable("tab");
+    table.addColumn(new MColumn("id","bigint"));
+    table.addColumn(new MColumn("name","varchar(20)"));
+    table.addColumn(new MColumn("comment","varchar(1000)"));
+
+    return table;
+  }
+
+  MTable newTableAdd2Columns() {
+    MTable table = new MTable("tab");
+    table.addColumn(new MColumn("id","bigint"));
+    table.addColumn(new MColumn("name","varchar(20)"));
+    table.addColumn(new MColumn("status","varchar(3)"));
+    table.addColumn(new MColumn("comment","varchar(1000)"));
+    table.addColumn(new MColumn("note","varchar(2000)"));
+    return table;
+  }
+
+  MTable newTableModifiedColumn() {
+    MColumn modCol = new MColumn("name", "varchar(30)");// modified type
+    modCol.setNotnull(true);
+
+    MTable table = new MTable("tab");
+    table.addColumn(modCol);
+    table.addColumn(new MColumn("id","bigint"));
+    table.addColumn(new MColumn("status","varchar(3)"));
+    return table;
+  }
+
+  @Test
+  public void testCompare_addColumnDropColumn() throws Exception {
+
+    ModelDiff diff = new ModelDiff();
+    diff.compareTables(base(), newTable());
+
+    List<Object> createChanges = diff.getCreateChanges();
+    assertThat(createChanges).hasSize(1);
+    AddColumn addColumn = (AddColumn)createChanges.get(0);
+    assertThat(addColumn.getColumn()).extracting("name").contains("comment");
+    assertThat(addColumn.getColumn()).extracting("type").contains("varchar(1000)");
+
+    List<Object> dropChanges = diff.getDropChanges();
+    assertThat(dropChanges).hasSize(1);
+
+    DropColumn dropColumn = (DropColumn)dropChanges.get(0);
+    assertThat(dropColumn.getColumnName()).isEqualTo("status");
+    assertThat(dropColumn.getTableName()).isEqualTo("tab");
+  }
+
+  @Test
+  public void testCompare_addTwoColumnsToSameTable() throws Exception {
+
+    ModelDiff diff = new ModelDiff();
+    diff.compareTables(base(), newTableAdd2Columns());
+
+    List<Object> createChanges = diff.getCreateChanges();
+    assertThat(createChanges).hasSize(1);
+
+    AddColumn addColumn = (AddColumn)createChanges.get(0);
+    assertThat(addColumn.getColumn()).extracting("name").contains("comment","note");
+    assertThat(addColumn.getColumn()).extracting("type").contains("varchar(1000)","varchar(2000)");
+
+    assertThat(diff.getDropChanges()).hasSize(0);
+
+  }
+
+  @Test
+  public void testCompare_modifyColumn() throws Exception {
+
+    ModelDiff diff = new ModelDiff();
+    diff.compareTables(base(), newTableModifiedColumn());
+
+    List<Object> createChanges = diff.getCreateChanges();
+    assertThat(createChanges).hasSize(1);
+
+    AlterColumn alterColumn = (AlterColumn)createChanges.get(0);
+    assertThat(alterColumn.getColumnName()).isEqualTo("name");
+    assertThat(alterColumn.getType()).isEqualTo("varchar(30)");
+    assertThat(alterColumn.isNotnull()).isEqualTo(true);
+    assertThat(alterColumn.isUnique()).isNull();
+    assertThat(alterColumn.getNewCheckConstraint()).isNull();
+    assertThat(alterColumn.getNewReferences()).isNull();
+
+    assertThat(diff.getDropChanges()).hasSize(0);
+
+  }
+}

src/test/java/com/avaje/ebean/dbmigration/model/MigrationModelTest.java

@@ -0,0 +1,39 @@
+package com.avaje.ebean.dbmigration.model;
+
+import org.junit.Test;
+
+import static org.assertj.core.api.Assertions.*;
+
+public class MigrationModelTest {
+
+  @Test
+  public void testRead() throws Exception {
+
+    MigrationModel migrationModel = new MigrationModel("dbmigration/app1");
+    ModelContainer model = migrationModel.read();
+
+    assertThat(migrationModel.getReadVersions()).contains("1.0","1.1","2.0");
+    assertThat(model.getTable("v10_table")).isNotNull();
+  }
+
+  @Test
+  public void testRead_leadingSlash() throws Exception {
+
+    MigrationModel migrationModel = new MigrationModel("/dbmigration/app1");
+    ModelContainer model = migrationModel.read();
+
+    assertThat(migrationModel.getReadVersions()).contains("1.0","1.1","2.0");
+    assertThat(model.getTable("v10_table")).isNotNull();
+  }
+
+  @Test
+  public void testRead_trailingSlash() throws Exception {
+
+    MigrationModel migrationModel = new MigrationModel("/dbmigration/app1/");
+    ModelContainer model = migrationModel.read();
+
+    assertThat(migrationModel.getReadVersions()).contains("1.0","1.1","2.0");
+    assertThat(model.getTable("v10_table")).isNotNull();
+  }
+
+}

src/test/java/com/avaje/ebean/dbmigration/model/ModelContainerApplyTest.java

@@ -32,7 +32,7 @@ public class ModelContainerApplyTest {
     model.apply(migration);
 
     MTable foo = model.getTable("foo");
-    assertThat(foo.getRemarks()).isEqualTo("comment");
+    assertThat(foo.getComment()).isEqualTo("comment");
     assertThat(foo.getTablespace()).isEqualTo("fooSpace");
     assertThat(foo.getIndexTablespace()).isEqualTo("fooIndexSpace");
     assertThat(foo.getWithHistory()).isEqualTo(true);

src/test/java/com/avaje/ebeaninternal/server/type/ScalarTypeJodaLocalDateTimeTest.java

@@ -0,0 +1,43 @@
+package com.avaje.ebeaninternal.server.type;
+
+import com.avaje.ebean.config.JsonConfig;
+import org.joda.time.DateTimeZone;
+import org.joda.time.LocalDateTime;
+import org.junit.Test;
+
+import java.sql.Timestamp;
+
+import static org.junit.Assert.*;
+
+public class ScalarTypeJodaLocalDateTimeTest {
+
+  ScalarTypeJodaLocalDateTime type = new ScalarTypeJodaLocalDateTime(JsonConfig.DateTime.ISO8601);
+
+  @Test
+  public void testConvertFromTimestamp() throws Exception {
+
+    long now = System.currentTimeMillis();
+    Timestamp nowTs = new Timestamp(now);
+
+    LocalDateTime ldt1 = type.convertFromTimestamp(nowTs);
+    LocalDateTime ldt2 = localConvertFromTimestamp(nowTs);
+
+    assertEquals(ldt1, ldt2);
+
+    Timestamp ts1 = type.convertToTimestamp(ldt1);
+    Timestamp ts2 = localConvertToTimestamp(ldt2);
+
+    assertEquals(ts1, ts2);
+  }
+
+
+  LocalDateTime localConvertFromTimestamp(Timestamp ts) {
+    return new LocalDateTime(ts.getTime(), DateTimeZone.getDefault());
+  }
+
+
+  Timestamp localConvertToTimestamp(LocalDateTime t) {
+    return new Timestamp(t.toDateTime(DateTimeZone.getDefault()).getMillis());
+  }
+
+}

src/test/java/com/avaje/ebeaninternal/server/type/ScalarTypeJodaLocalTimeTest.java

@@ -0,0 +1,32 @@
+package com.avaje.ebeaninternal.server.type;
+
+import org.joda.time.DateTimeZone;
+import org.joda.time.LocalDateTime;
+import org.junit.Test;
+
+import java.sql.Timestamp;
+
+import static org.junit.Assert.assertEquals;
+
+public class ScalarTypeJodaLocalTimeTest {
+
+  @Test
+  public void test() {
+
+    long now = System.currentTimeMillis();
+
+    //DateTimeZone timeZone = DateTimeZone.getDefault();
+    //ISOChronology instance = ISOChronology.getInstance();
+
+    LocalDateTime ldt1 = new LocalDateTime(now, DateTimeZone.getDefault());
+    LocalDateTime ldt2 = new LocalDateTime(now);
+
+    assertEquals(ldt1, ldt2);
+
+    Timestamp ts1 = new Timestamp(ldt1.toDateTime(DateTimeZone.getDefault()).getMillis());
+    Timestamp ts2 = new Timestamp(ldt2.toDateTime().getMillis());
+
+    assertEquals(ts1, ts2);
+
+  }
+}

src/test/resources/dbmigration/app1/v1.0.xml

@@ -13,7 +13,7 @@
       </rollback>
     </sql>
 
-    <createTable name="dbmigration">
+    <createTable name="v10_table">
       <column name="application" type="varchar(30)" notnull="true"/>
       <column name="change_log"  type="integer"     notnull="true"/>
       <column name="change_set"  type="integer"     notnull="true"/>
@@ -21,17 +21,6 @@
       <column name="locked_at"   type="timestamp"/>
     </createTable>
 
-    <createTable name="dbmigration_changeset">
-      <column name="id"          type="integer"      primaryKey="true"/>
-      <column name="application" type="varchar(30)"  notnull="true" references="dbmigration.application"/>
-      <column name="change_log"  type="integer"      notnull="true"/>
-      <column name="change_set"  type="integer"      notnull="true"/>
-      <column name="run_at"      type="timestamp"    notnull="true"/>
-      <column name="run_by"      type="varchar(30)"  notnull="true"/>
-      <column name="run_ddl"     type="clob"/>
-      <column name="run_log"     type="clob"/>
-    </createTable>
-
     <createTable name="hello_world" withHistory="true">
       <column name="id" type="integer" primaryKey="true"/>
       <column name="name" type="varchar(20)" notnull="true"/>
@@ -47,7 +36,7 @@
 
     <createHistoryTable baseTable="hello_world"/>
 
-    <addForeignKey name="fk_hello_world_x" columns="x" references="asdsad.asd"/>
+    <!--<addForeignKey name="fk_hello_world_x" columns="x" references="asdsad.asd"/>-->
 
   </changeSet>
 

src/test/resources/dbmigration/app1/v1.1.xml

@@ -13,7 +13,7 @@
       </rollback>
     </sql>
 
-    <createTable name="dbmigration">
+    <createTable name="v11_table">
       <column name="application" type="varchar(30)" notnull="true"/>
       <column name="change_log"  type="integer"     notnull="true"/>
       <column name="change_set"  type="integer"     notnull="true"/>
@@ -21,34 +21,6 @@
       <column name="locked_at"   type="timestamp"/>
     </createTable>
 
-    <createTable name="dbmigration_changeset">
-      <column name="id"          type="integer"      primaryKey="true"/>
-      <column name="application" type="varchar(30)"  notnull="true" references="dbmigration.application"/>
-      <column name="change_log"  type="integer"      notnull="true"/>
-      <column name="change_set"  type="integer"      notnull="true"/>
-      <column name="run_at"      type="timestamp"    notnull="true"/>
-      <column name="run_by"      type="varchar(30)"  notnull="true"/>
-      <column name="run_ddl"     type="clob"/>
-      <column name="run_log"     type="clob"/>
-    </createTable>
-
-    <createTable name="hello_world" withHistory="true">
-      <column name="id" type="integer" primaryKey="true"/>
-      <column name="name" type="varchar(20)" notnull="true"/>
-      <column name="type" type="varchar(20)" notnull="true"/>
-      <column name="description" type="varchar(20)" notnull="true"/>
-      <uniqueConstraint columnNames="name,type"/>
-    </createTable>
-
-    <addColumn tableName="hello_world">
-      <column name="fooe" type="varchar(20)"/>
-    </addColumn>
-
-
-    <createHistoryTable baseTable="hello_world"/>
-
-    <addForeignKey name="fk_hello_world_x" columns="x" references="asdsad.asd"/>
-
   </changeSet>
 
   <changeSet type="drop" generated="true">

src/test/resources/dbmigration/app1/v10.0.xml

@@ -1,53 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<migration xmlns="http://ebean-orm.github.io/xml/ns/dbmigration" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-           xsi:schemaLocation="http://ebean-orm.github.io/xml/ns/dbmigration http://ebean-orm.github.io/xml/ns/dbmigration-1.0.xsd">
-
-  <changeSet type="apply">
-
-    <sql>
-      <apply>
-        create table foo;
-      </apply>
-      <rollback>
-        drop table if exists foo;
-      </rollback>
-    </sql>
-
-    <createTable name="dbmigration_lock">
-      <column name="application" type="varchar(30)" notnull="true"/>
-      <column name="locked_by"   type="varchar(30)"/>
-      <column name="locked_at"   type="timestamp"/>
-    </createTable>
-
-    <createTable name="dbmigration_run">
-      <column name="id"          type="integer"      primaryKey="true"/>
-      <column name="application" type="varchar(30)"  notnull="true" references="dbmigration.application"/>
-      <column name="version"     type="varchar(3)"   notnull="true"/>
-      <column name="run_at"      type="timestamp"    notnull="true"/>
-      <column name="run_by"      type="varchar(30)"  notnull="true"/>
-      <column name="run_status"  type="varchar(30)"  notnull="true"/>
-      <column name="run_ddl"     type="clob"/>
-      <column name="run_log"     type="clob"/>
-    </createTable>
-
-    <createTable name="hello_world" withHistory="true">
-      <column name="id" type="integer" primaryKey="true"/>
-      <column name="name" type="varchar(20)" notnull="true"/>
-      <column name="description" type="varchar(20)" notnull="true"/>
-    </createTable>
-
-    <addColumn tableName="hello_world">
-      <column name="fooe" type="varchar(20)"/>
-    </addColumn>
-
-    <dropColumn columnName="fooe" tableName="hello_world"/>
-
-    <createHistoryTable baseTable="hello_world"/>
-
-  </changeSet>
-
-  <changeSet type="drop" generated="true">
-    <!-- no drops to do -->
-  </changeSet>
-
-</migration>

src/test/resources/dbmigration/app1/v2.0.xml

@@ -13,39 +13,6 @@
       </rollback>
     </sql>
 
-    <createTable name="dbmigration">
-      <column name="application" type="varchar(30)" notnull="true"/>
-      <column name="change_log"  type="integer"     notnull="true"/>
-      <column name="change_set"  type="integer"     notnull="true"/>
-      <column name="locked_by"   type="varchar(30)"/>
-      <column name="locked_at"   type="timestamp"/>
-    </createTable>
-
-    <createTable name="dbmigration_changeset">
-      <column name="id"          type="integer"      primaryKey="true"/>
-      <column name="application" type="varchar(30)"  notnull="true" references="dbmigration.application"/>
-      <column name="change_log"  type="integer"      notnull="true"/>
-      <column name="change_set"  type="integer"      notnull="true"/>
-      <column name="run_at"      type="timestamp"    notnull="true"/>
-      <column name="run_by"      type="varchar(30)"  notnull="true"/>
-      <column name="run_ddl"     type="clob"/>
-      <column name="run_log"     type="clob"/>
-    </createTable>
-
-    <createTable name="hello_world" withHistory="true">
-      <column name="id" type="integer" primaryKey="true"/>
-      <column name="name" type="varchar(20)" notnull="true"/>
-      <column name="description" type="varchar(20)" notnull="true"/>
-    </createTable>
-
-    <addColumn tableName="hello_world">
-      <column name="fooe" type="varchar(20)"/>
-    </addColumn>
-
-    <dropColumn columnName="fooe" tableName="hello_world"/>
-
-    <createHistoryTable baseTable="hello_world"/>
-
   </changeSet>
 
   <changeSet type="drop" generated="true">

src/test/resources/dbmigration/app1/v9.0.xml

@@ -1,55 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<migration xmlns="http://ebean-orm.github.io/xml/ns/dbmigration" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-           xsi:schemaLocation="http://ebean-orm.github.io/xml/ns/dbmigration http://ebean-orm.github.io/xml/ns/dbmigration-1.0.xsd">
-
-  <changeSet type="apply">
-
-    <sql>
-      <apply>
-        create table foo;
-      </apply>
-      <rollback>
-        drop table if exists foo;
-      </rollback>
-    </sql>
-
-    <createTable name="dbmigration">
-      <column name="application" type="varchar(30)" notnull="true"/>
-      <column name="change_log"  type="integer"     notnull="true"/>
-      <column name="change_set"  type="integer"     notnull="true"/>
-      <column name="locked_by"   type="varchar(30)"/>
-      <column name="locked_at"   type="timestamp"/>
-    </createTable>
-
-    <createTable name="dbmigration_changeset">
-      <column name="id"          type="integer"      primaryKey="true"/>
-      <column name="application" type="varchar(30)"  notnull="true" references="dbmigration.application"/>
-      <column name="change_log"  type="integer"      notnull="true"/>
-      <column name="change_set"  type="integer"      notnull="true"/>
-      <column name="run_at"      type="timestamp"    notnull="true"/>
-      <column name="run_by"      type="varchar(30)"  notnull="true"/>
-      <column name="run_ddl"     type="clob"/>
-      <column name="run_log"     type="clob"/>
-    </createTable>
-
-    <createTable name="hello_world" withHistory="true">
-      <column name="id" type="integer" primaryKey="true"/>
-      <column name="name" type="varchar(20)" notnull="true"/>
-      <column name="description" type="varchar(20)" notnull="true"/>
-    </createTable>
-
-    <addColumn tableName="hello_world">
-      <column name="fooe" type="varchar(20)"/>
-    </addColumn>
-
-    <dropColumn columnName="fooe" tableName="hello_world"/>
-
-    <createHistoryTable baseTable="hello_world"/>
-
-  </changeSet>
-
-  <changeSet type="drop" generated="true">
-    <!-- no drops to do -->
-  </changeSet>
-
-</migration>

src/test/resources/dbmigration/applications.xml

@@ -1,7 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<applications xmlns="http://ebean-orm.github.io/xml/ns/dbmigration" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-    xsi:schemaLocation="http://ebean-orm.github.io/xml/ns/dbmigration http://ebean-orm.github.io/xml/ns/dbmigration-1.0.xsd">
-
-  <application name="myapp" resourcePath="dbmigration/app1"/>
-
-</applications>

src/test/resources/ebean.properties

@@ -23,7 +23,7 @@ ebean.autofetch.traceUsageCollection=false
 
 ebean.ddl.generate=true
 ebean.ddl.run=true
-datasource.default=ms
+datasource.default=h2
 
 ebean.persistBatch=NONE
 ebean.persistBatchOnCascade=ALL
@@ -46,6 +46,9 @@ ebean.cacheWarmingDelay=-1
 
 ##ebean.transaction.rollbackOnChecked=false
 
+ebean.migration.appName=myapp
+ebean.migration.resourcePath=dbmigration/myapp
+
 
 ## -------------------------------------------------------------
 ## DataSources (If using default Ebean DataSourceFactory)

src/test/resources/logback-test.xml

@@ -33,7 +33,7 @@
     <logger name="org.avaje.ebean.TXN" level="TRACE"/>
     <logger name="org.avaje.ebean.SUM" level="TRACE"/>
 
-    <logger name="com.avaje.ebeaninternal.server.ddl" level="TRACE"/>
+    <logger name="com.avaje.ebeaninternal.server.core" level="DEBUG"/>
 
     <logger name="org.avaje.ebean.cache.QUERY" level="TRACE"/>
     <logger name="org.avaje.ebean.cache.BEAN" level="TRACE"/>