#347 - @History support with query.asOf(Timestamp)

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 +96,17 @@ 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 the query iterating over the results.
    * 

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.

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/config/ServerConfig.java

@@ -144,6 +144,18 @@ 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";
+
   /**
    * Use for transaction scoped batch mode.
    */
@@ -579,6 +591,38 @@ public class ServerConfig {
     this.databaseSequenceBatchSize = databaseSequenceBatchSize;
   }
 
+  /**
+   * 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 true if we are running in a JTA Transaction manager.
    */
@@ -1809,6 +1853,8 @@ public class ServerConfig {
 
     persistenceContextScope = PersistenceContextScope.valueOf(p.get("persistenceContextScope", "TRANSACTION"));
 
+    asOfViewSuffix = p.get("asOfViewSuffix", asOfViewSuffix);
+    asOfSysPeriod = p.get("asOfSysPeriod", asOfSysPeriod);
     dataSourceJndiName = p.get("dataSourceJndiName", dataSourceJndiName);
     databaseSequenceBatchSize = p.getInt("databaseSequenceBatchSize", databaseSequenceBatchSize);
     databaseBooleanTrue = p.get("databaseBooleanTrue", databaseBooleanTrue);

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

@@ -442,6 +442,10 @@ public class DatabasePlatform {
     return disallowBatchOnCascade;
   }
 
+  public String getAsOfPredicate(String asOfTableAlias, String asOfSysPeriod) {
+    throw new RuntimeException("AsOf query not support of this database platform yet");
+  }
+
   /**
    * Generate and return the create sequence DDL.
    */

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

@@ -60,12 +60,24 @@ public class PostgresPlatform extends DatabasePlatform {
 
   }
 
+  /**
+   * 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>
+   */
+  public String getAsOfPredicate(String asOfTableAlias, String asOfSysPeriod) {
+
+    StringBuilder sb = new StringBuilder(40);
+    sb.append(asOfTableAlias).append(".").append(asOfSysPeriod).append(" @> ?::timestamptz");
+    return sb.toString();
+  }
+
   /**
    * 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/ebeaninternal/api/SpiQuery.java

@@ -19,6 +19,7 @@ import com.avaje.ebeaninternal.server.querydefn.NaturalKeyBindParam;
 import com.avaje.ebeaninternal.server.querydefn.OrmQueryDetail;
 import com.avaje.ebeaninternal.server.querydefn.OrmQueryProperties;
 
+import java.sql.Timestamp;
 import java.util.List;
 
 /**
@@ -86,6 +87,30 @@ public interface SpiQuery<T> extends Query<T> {
     SUBQUERY
   }
 
+  enum TemporalMode {
+    /**
+     * Query runs against current data (normal).
+     */
+    CURRENT,
+
+    /**
+     * Query runs potentially returning many versions of the same bean.
+     */
+    VERSIONS,
+
+    /**
+     * Query runs 'As Of' a given date time.
+     */
+    AS_OF;
+
+    /**
+     * Return the mode of the query of if null return CURRENT mode.
+     */
+    public static TemporalMode of(SpiQuery<?> query) {
+      return (query != null) ? query.getTemporalMode() : TemporalMode.CURRENT;
+    }
+  }
+
   /**
    * Return the PersistenceContextScope that this query should use.
    * <p>
@@ -115,6 +140,31 @@ public interface SpiQuery<T> extends Query<T> {
    */
   Mode getMode();
 
+  /**
+   * Return the Temporal mode for the query.
+   */
+  TemporalMode getTemporalMode();
+
+  /**
+   * Return true if this is a 'As Of' query.
+   */
+  boolean isAsOfQuery();
+
+  /**
+   * Return the asOf Timestamp which the query should run as.
+   */
+  Timestamp getAsOf();
+
+  /**
+   * Add a table alias for a @History entity involved in a 'As Of' query.
+   */
+  void addAsOfTableAlias(String tableAlias);
+
+  /**
+   * Return the list of table alias involved in a 'As Of' query that have @History support.
+   */
+  List<String> getAsOfTableAlias();
+
   /**
    * Return a listener that wants to be notified when the bean collection is
    * first used.

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

@@ -41,6 +41,8 @@ import com.avaje.ebeaninternal.server.type.DefaultTypeManager;
 import com.avaje.ebeaninternal.server.type.TypeManager;
 import com.fasterxml.jackson.core.JsonFactory;
 
+import java.util.Map;
+
 /**
  * Used to extend the ServerConfig with additional objects used to configure and
  * construct an EbeanServer.
@@ -116,11 +118,11 @@ public class InternalConfiguration {
     this.deployUtil = new DeployUtil(typeManager, serverConfig);
 
     this.beanDescriptorManager = new BeanDescriptorManager(this);
-    beanDescriptorManager.deploy();
+    Map<String, String> asOfTableMapping = beanDescriptorManager.deploy();
 
     this.transactionManager = createTransactionManager();
 
-    this.cQueryEngine = new CQueryEngine(serverConfig.getDatabasePlatform(), binder);
+    this.cQueryEngine = new CQueryEngine(serverConfig.getDatabasePlatform(), binder, asOfTableMapping, serverConfig.getAsOfSysPeriod());
 
     ExternalTransactionManager externalTransactionManager = serverConfig.getExternalTransactionManager();
     if (externalTransactionManager == null && serverConfig.isUseJtaTransactionManager()) {

src/main/java/com/avaje/ebeaninternal/server/deploy/BeanDescriptor.java

@@ -112,6 +112,8 @@ public class BeanDescriptor<T> implements MetaBeanInfo {
    * The base database table.
    */
   private final String baseTable;
+  private final String baseTableAsOf;
+  private final boolean historySupport;
 
   /**
    * Map of BeanProperty Linked so as to preserve order.
@@ -332,8 +334,9 @@ public class BeanDescriptor<T> implements MetaBeanInfo {
     this.updateChangesOnly = deploy.isUpdateChangesOnly();
     this.compoundUniqueConstraints = deploy.getCompoundUniqueConstraints();
 
+    this.historySupport = deploy.isHistorySupport();
     this.baseTable = InternString.intern(deploy.getBaseTable());
-
+    this.baseTableAsOf = deploy.getBaseTableAsOf();
     this.autoFetchTunable = EntityType.ORM.equals(entityType) && (beanFinder == null);
 
     // helper object used to derive lists of properties
@@ -496,13 +499,19 @@ public class BeanDescriptor<T> implements MetaBeanInfo {
    * These properties need to be initialised prior to the association properties
    * as they are used to get the imported and exported properties.
    * </p>
+   * @param withHistoryTables map populated if @History is supported on this entity bean
    */
-  public void initialiseId() {
+  public void initialiseId(Map<String, String> withHistoryTables) {
 
     if (logger.isTraceEnabled()) {
       logger.trace("BeanDescriptor initialise " + fullName);
     }
 
+    if (historySupport) {
+      // add mapping (used to swap out baseTable for asOf queries)
+      withHistoryTables.put(baseTable, baseTableAsOf);
+    }
+
     if (inheritInfo != null) {
       inheritInfo.setDescriptor(this);
     }
@@ -522,8 +531,25 @@ public class BeanDescriptor<T> implements MetaBeanInfo {
 
   /**
    * Initialise the exported and imported parts for associated properties.
+   *
+   * @param asOfTableMap the map of base tables to associated 'with history' tables
+   * @param asOfViewSuffix the suffix added to the table name to derive the 'with history' view name
    */
-  public void initialiseOther() {
+  public void initialiseOther(Map<String, String> asOfTableMap, String asOfViewSuffix) {
+
+    if (historySupport) {
+      // history support on this bean so check all associated intersection tables
+      // and if they are not excluded register the associated 'with history' table
+      for (int i = 0; i < propertiesManyToMany.length; i++) {
+        if (!propertiesManyToMany[i].isExcludedFromHistory()) {
+          // this intersection table has history support so also register
+          // it into the asOfTableMap
+          TableJoin intersectionTableJoin = propertiesManyToMany[i].getIntersectionTableJoin();
+          String intersectionTableName = intersectionTableJoin.getTable();
+          asOfTableMap.put(intersectionTableName, intersectionTableName + asOfViewSuffix);
+        }
+      }
+    }
 
     if (!isEmbedded()) {
       // initialise all the non-id properties
@@ -761,7 +787,7 @@ public class BeanDescriptor<T> implements MetaBeanInfo {
   }
 
   public void cacheBeanPut(T bean) {
-    cacheBeanPutData((EntityBean)bean);
+    cacheBeanPutData((EntityBean) bean);
   }
   
   /**
@@ -1628,6 +1654,24 @@ public class BeanDescriptor<T> implements MetaBeanInfo {
     return baseTable;
   }
 
+  /**
+   * Return the base table to use given the query temporal mode.
+   */
+  public String getBaseTable(SpiQuery.TemporalMode mode) {
+    switch (mode) {
+      case VERSIONS: return baseTableAsOf;
+      case AS_OF: return baseTableAsOf;
+        default: return baseTable;
+    }
+  }
+
+  /**
+   * Return true if this entity bean has history support.
+   */
+  public boolean isHistorySupport() {
+    return historySupport;
+  }
+
   /**
    * Return the identity generation type.
    */

src/main/java/com/avaje/ebeaninternal/server/deploy/BeanDescriptorManager.java

@@ -10,6 +10,7 @@ import com.avaje.ebean.cache.ServerCacheManager;
 import com.avaje.ebean.config.EncryptKey;
 import com.avaje.ebean.config.EncryptKeyManager;
 import com.avaje.ebean.config.NamingConvention;
+import com.avaje.ebean.config.ServerConfig;
 import com.avaje.ebean.config.dbplatform.DatabasePlatform;
 import com.avaje.ebean.config.dbplatform.DbIdentity;
 import com.avaje.ebean.config.dbplatform.IdGenerator;
@@ -51,7 +52,7 @@ public class BeanDescriptorManager implements BeanDescriptorMap {
 
   private static final BeanDescComparator beanDescComparator = new BeanDescComparator();
 
-  private final ReadAnnotations readAnnotations = new ReadAnnotations();
+  private final ReadAnnotations readAnnotations;
 
   private final TransientProperties transientProperties;
 
@@ -127,34 +128,45 @@ public class BeanDescriptorManager implements BeanDescriptorMap {
 
   private final boolean eagerFetchLobs;
 
+  private final String asOfViewSuffix;
+
+  /**
+   * Map of base tables to 'with history views' used to support 'as of' queries.
+   */
+  private final Map<String,String> asOfTableMap = new HashMap<String, String>();
+
   /**
    * Create for a given database dbConfig.
    */
   public BeanDescriptorManager(InternalConfiguration config) {
 
-    this.serverName = InternString.intern(config.getServerConfig().getName());
+    ServerConfig serverConfig = config.getServerConfig();
+
+    this.serverName = InternString.intern(serverConfig.getName());
     this.cacheManager = config.getCacheManager();
     this.xmlConfig = config.getXmlConfig();
-    this.dbSequenceBatchSize = config.getServerConfig().getDatabaseSequenceBatchSize();
+    this.dbSequenceBatchSize = serverConfig.getDatabaseSequenceBatchSize();
     this.backgroundExecutor = config.getBackgroundExecutor();
-    this.dataSource = config.getServerConfig().getDataSource();
-    this.encryptKeyManager = config.getServerConfig().getEncryptKeyManager();
-    this.databasePlatform = config.getServerConfig().getDatabasePlatform();
+    this.dataSource = serverConfig.getDataSource();
+    this.encryptKeyManager = serverConfig.getEncryptKeyManager();
+    this.databasePlatform = serverConfig.getDatabasePlatform();
     this.idBinderFactory = new IdBinderFactory(databasePlatform.isIdInExpandedForm());
-    this.eagerFetchLobs = config.getServerConfig().isEagerFetchLobs();
+    this.eagerFetchLobs = serverConfig.isEagerFetchLobs();
 
+    this.asOfViewSuffix = serverConfig.getAsOfViewSuffix();
+    this.readAnnotations = new ReadAnnotations(asOfViewSuffix);
     this.bootupClasses = config.getBootupClasses();
     this.createProperties = config.getDeployCreateProperties();
     this.typeManager = config.getTypeManager();
-    this.namingConvention = config.getServerConfig().getNamingConvention();
+    this.namingConvention = serverConfig.getNamingConvention();
     this.dbIdentity = config.getDatabasePlatform().getDbIdentity();
     this.deplyInherit = config.getDeployInherit();
     this.deployOrmXml = config.getDeployOrmXml();
     this.deployUtil = config.getDeployUtil();
 
-    this.beanManagerFactory = new BeanManagerFactory(config.getServerConfig(), config.getDatabasePlatform());
+    this.beanManagerFactory = new BeanManagerFactory(serverConfig, config.getDatabasePlatform());
 
-    this.updateChangesOnly = config.getServerConfig().isUpdateChangesOnly();
+    this.updateChangesOnly = serverConfig.isUpdateChangesOnly();
 
     this.beanLifecycleAdapterFactory = new BeanLifecycleAdapterFactory();
     this.persistControllerManager = new PersistControllerManager(bootupClasses);
@@ -205,7 +217,10 @@ public class BeanDescriptorManager implements BeanDescriptorMap {
     return idBinderFactory.createIdBinder(idProperty);
   }
 
-  public void deploy() {
+  /**
+   * Deploy returning the asOfTableMap (which is required by the SQL builders).
+   */
+  public Map<String,String> deploy() {
 
     try {
       createListeners();
@@ -237,6 +252,9 @@ public class BeanDescriptorManager implements BeanDescriptorMap {
 
       deplyInfoMap.clear();
       deplyInfoMap = null;
+
+      return asOfTableMap;
+
     } catch (RuntimeException e) {
       String msg = "Error in deployment";
       logger.error(msg, e);
@@ -324,7 +342,7 @@ public class BeanDescriptorManager implements BeanDescriptorMap {
     // first (as they are needed to initialise the
     // associated properties in the second pass).
     for (BeanDescriptor<?> d : descMap.values()) {
-      d.initialiseId();
+      d.initialiseId(asOfTableMap);
     }
 
     // PASS 2:
@@ -336,7 +354,10 @@ public class BeanDescriptorManager implements BeanDescriptorMap {
     // PASS 3:
     // now initialise all the associated properties
     for (BeanDescriptor<?> d : descMap.values()) {
-      d.initialiseOther();
+      // also look for intersection tables with
+      // associated history support and register them
+      // into the asOfTableMap
+      d.initialiseOther(asOfTableMap, asOfViewSuffix);
     }
 
     // create BeanManager for each non-embedded entity bean
@@ -973,7 +994,7 @@ public class BeanDescriptorManager implements BeanDescriptorMap {
 
     if (!EntityType.ORM.equals(desc.getEntityType())) {
       // not using base table
-      desc.setBaseTable(null);
+      desc.setBaseTable(null, null);
     }
 
     // mark transient properties

src/main/java/com/avaje/ebeaninternal/server/deploy/BeanProperty.java

@@ -173,6 +173,8 @@ public class BeanProperty implements ElPropertyValue {
    */
   final int dbType;
 
+  final boolean excludedFromHistory;
+
   /**
    * The default value to insert if null.
    */
@@ -256,6 +258,7 @@ public class BeanProperty implements ElPropertyValue {
     this.dbRead = deploy.isDbRead();
     this.dbInsertable = deploy.isDbInsertable();
     this.dbUpdatable = deploy.isDbUpdateable();
+    this.excludedFromHistory = deploy.isExcludedFromHistory();
 
     this.secondaryTable = deploy.isSecondaryTable();
     if (secondaryTable) {
@@ -341,6 +344,7 @@ public class BeanProperty implements ElPropertyValue {
     this.sqlFormulaSelect = InternString.intern(override.getSqlFormulaSelect());
     this.formula = sqlFormulaSelect != null;
 
+    this.excludedFromHistory = source.excludedFromHistory;
     this.fetchEager = source.fetchEager;
     this.unidirectionalShadow = source.unidirectionalShadow;
     this.discriminator = source.discriminator;
@@ -1004,6 +1008,13 @@ public class BeanProperty implements ElPropertyValue {
     return dbEncryptedType;
   }
 
+  /**
+   * Return true if this property is excluded from history.
+   */
+  public boolean isExcludedFromHistory() {
+    return excludedFromHistory;
+  }
+
   /**
    * Return true if this property should be included in an Insert.
    */

src/main/java/com/avaje/ebeaninternal/server/deploy/DbSqlContext.java

@@ -10,108 +10,108 @@ public interface DbSqlContext {
   /**
    * Add a join to the sql query.
    */
-  public void addJoin(String type, String table, TableJoinColumn[] cols, String a1, String a2, String inheritance);
+  void addJoin(String type, String table, TableJoinColumn[] cols, String a1, String a2, String inheritance);
 
-  public void pushSecondaryTableAlias(String alias);
+  void pushSecondaryTableAlias(String alias);
 
   /**
    * Push the current table alias onto the stack.
    */
-  public void pushTableAlias(String tableAlias);
+  void pushTableAlias(String tableAlias);
 
   /**
    * Pop the current table alias from the stack.
    */
-  public void popTableAlias();
+  void popTableAlias();
 
   /**
    * Add an encrypted property which will require additional binding.
    */
-  public void addEncryptedProp(BeanProperty prop);
+  void addEncryptedProp(BeanProperty prop);
 
   /**
    * Return a list of encrypted properties which require additional binding.
    */
-  public BeanProperty[] getEncryptedProps();
+  BeanProperty[] getEncryptedProps();
 
   /**
    * Append a char directly to the SQL buffer.
    */
-  public DbSqlContext append(char s);
+  DbSqlContext append(char s);
 
   /**
    * Append a string directly to the SQL buffer.
    */
-  public DbSqlContext append(String s);
+  DbSqlContext append(String s);
 
   /**
    * Peek the current table alias.
    */
-  public String peekTableAlias();
+  String peekTableAlias();
 
   /**
    * Add a raw column to the sql.
    */
-  public void appendRawColumn(String rawcolumnWithTableAlias);
+  void appendRawColumn(String rawcolumnWithTableAlias);
 
   /**
    * Append a column with an explicit table alias.
    */
-  public void appendColumn(String tableAlias, String column);
+  void appendColumn(String tableAlias, String column);
 
   /**
    * Append a column with the current table alias.
    */
-  public void appendColumn(String column);
+  void appendColumn(String column);
 
   /**
    * Append a Sql Formula select. This converts the "${ta}" keyword to the
    * current table alias.
    */
-  public void appendFormulaSelect(String sqlFormulaSelect);
+  void appendFormulaSelect(String sqlFormulaSelect);
 
   /**
    * Append a Sql Formula join. This converts the "${ta}" keyword to the current
    * table alias.
    */
-  public void appendFormulaJoin(String sqlFormulaJoin, SqlJoinType joinType);
+  void appendFormulaJoin(String sqlFormulaJoin, SqlJoinType joinType);
 
   /**
    * Return the current content length.
    */
-  public int length();
+  int length();
 
   /**
    * Return the current context of the sql context.
    */
-  public String getContent();
+  String getContent();
 
   /**
    * Return the current join node.
    */
-  public String peekJoin();
+  String peekJoin();
 
   /**
    * Push a join node onto the stack.
    */
-  public void pushJoin(String prefix);
+  void pushJoin(String prefix);
 
   /**
    * Pop a join node off the stack.
    */
-  public void popJoin();
+  void popJoin();
 
   /**
    * Return a table alias without many where clause joins. Typically this is for
    * the select clause (fetch joins).
    */
-  public String getTableAlias(String prefix);
+  String getTableAlias(String prefix);
 
   /**
    * Return a table alias that takes into account many where joins.
    */
-  public String getTableAliasManyWhere(String prefix);
+  String getTableAliasManyWhere(String prefix);
 
-  public String getRelativePrefix(String propName);
+  String getRelativePrefix(String propName);
 
 }

src/main/java/com/avaje/ebeaninternal/server/deploy/meta/DeployBeanDescriptor.java

@@ -87,6 +87,11 @@ public class DeployBeanDescriptor<T> {
    * The base database table.
    */
   private String baseTable;
+
+  private String baseTableAsOf;
+
+  private boolean historySupport;
+
   private TableName baseTableFull;
 
   private String[] properties;
@@ -135,6 +140,20 @@ public class DeployBeanDescriptor<T> {
     return Modifier.isAbstract(beanType.getModifiers());
   }
 
+  /**
+   * Set to true for @History entity beans that have history.
+   */
+  public void setHistorySupport(boolean historySupport) {
+    this.historySupport = historySupport;
+  }
+
+  /**
+   * Return true if this is an @History entity bean.
+   */
+  public boolean isHistorySupport() {
+    return historySupport;
+  }
+
   public boolean isScalaObject() {
     Class<?>[] interfaces = beanType.getInterfaces();
     for (int i = 0; i < interfaces.length; i++) {
@@ -405,6 +424,10 @@ public class DeployBeanDescriptor<T> {
     return baseTable;
   }
 
+  public String getBaseTableAsOf() {
+    return baseTableAsOf;
+  }
+
   /**
    * Return the base table with full structure.
    */
@@ -413,12 +436,12 @@ public class DeployBeanDescriptor<T> {
   }
 
   /**
-   * Set the base table. Only properties mapped to the base table are by default
-   * persisted.
+   * Set the base table. Only properties mapped to the base table are by default persisted.
    */
-  public void setBaseTable(TableName baseTableFull) {
+  public void setBaseTable(TableName baseTableFull, String asOfSuffix) {
     this.baseTableFull = baseTableFull;
     this.baseTable = baseTableFull == null ? null : baseTableFull.getQualifiedName();
+    this.baseTableAsOf = baseTable + asOfSuffix;
   }
 
   public void sortProperties() {

src/main/java/com/avaje/ebeaninternal/server/deploy/meta/DeployBeanProperty.java

@@ -215,6 +215,8 @@ public class DeployBeanProperty {
   private boolean indexed;
   private String indexName;
 
+  private boolean excludedFromHistory;
+
   public DeployBeanProperty(DeployBeanDescriptor<?> desc, Class<?> propertyType, ScalarType<?> scalarType, ScalarTypeConverter<?, ?> typeConverter) {
     this.desc = desc;
     this.propertyType = propertyType;
@@ -912,4 +914,12 @@ public class DeployBeanProperty {
   public void setIndexName(String indexName) {
     this.indexName = indexName;
   }
+
+  public boolean isExcludedFromHistory() {
+    return excludedFromHistory;
+  }
+
+  public void setExcludedFromHistory(boolean excludedFromHistory) {
+    this.excludedFromHistory = excludedFromHistory;
+  }
 }

src/main/java/com/avaje/ebeaninternal/server/deploy/parse/AnnotationAssocManys.java

@@ -8,6 +8,7 @@ import javax.persistence.MapKey;
 import javax.persistence.OneToMany;
 import javax.persistence.OrderBy;
 
+import com.avaje.ebean.annotation.HistoryExclude;
 import com.avaje.ebean.annotation.PrivateOwned;
 import com.avaje.ebean.annotation.Where;
 import com.avaje.ebean.bean.BeanCollection.ModifyListenMode;
@@ -65,7 +66,11 @@ public class AnnotationAssocManys extends AnnotationParser {
 			readToMany(manyToMany, prop);
 		}
 
-		OrderBy orderBy = get(prop, OrderBy.class);
+    if (get(prop, HistoryExclude.class) != null) {
+      prop.setExcludedFromHistory(true);
+    }
+
+    OrderBy orderBy = get(prop, OrderBy.class);
 		if (orderBy != null) {
 			prop.setFetchOrderBy(orderBy.value());
 		}

src/main/java/com/avaje/ebeaninternal/server/deploy/parse/AnnotationClass.java

@@ -10,6 +10,7 @@ import javax.persistence.UniqueConstraint;
 import com.avaje.ebean.annotation.CacheStrategy;
 import com.avaje.ebean.annotation.CacheTuning;
 import com.avaje.ebean.annotation.EntityConcurrencyMode;
+import com.avaje.ebean.annotation.History;
 import com.avaje.ebean.annotation.NamedUpdate;
 import com.avaje.ebean.annotation.NamedUpdates;
 import com.avaje.ebean.annotation.UpdateMode;
@@ -26,8 +27,11 @@ import com.avaje.ebeaninternal.server.deploy.meta.DeployBeanProperty;
  */
 public class AnnotationClass extends AnnotationParser {
 
-  public AnnotationClass(DeployBeanInfo<?> info) {
+  private final String asOfViewSuffix;
+
+  public AnnotationClass(DeployBeanInfo<?> info, String asOfViewSuffix) {
     super(info);
+    this.asOfViewSuffix = asOfViewSuffix;
   }
 
   /**
@@ -48,7 +52,7 @@ public class AnnotationClass extends AnnotationParser {
       // default the TableName using NamingConvention.
       TableName tableName = namingConvention.getTableName(descriptor.getBeanType());
 
-      descriptor.setBaseTable(tableName);
+      descriptor.setBaseTable(tableName, asOfViewSuffix);
     }
   }
 
@@ -84,6 +88,11 @@ public class AnnotationClass extends AnnotationParser {
       }
     }
 
+    History history = cls.getAnnotation(History.class);
+    if (history != null) {
+      descriptor.setHistorySupport(true);
+    }
+
     UpdateMode updateMode = cls.getAnnotation(UpdateMode.class);
     if (updateMode != null) {
       descriptor.setUpdateChangesOnly(updateMode.updateChangesOnly());

src/main/java/com/avaje/ebeaninternal/server/deploy/parse/AnnotationFields.java

@@ -8,6 +8,7 @@ import com.avaje.ebean.annotation.EmbeddedColumns;
 import com.avaje.ebean.annotation.Encrypted;
 import com.avaje.ebean.annotation.Expose;
 import com.avaje.ebean.annotation.Formula;
+import com.avaje.ebean.annotation.HistoryExclude;
 import com.avaje.ebean.annotation.Index;
 import com.avaje.ebean.annotation.JsonIgnore;
 import com.avaje.ebean.annotation.UpdatedTimestamp;
@@ -217,6 +218,10 @@ public class AnnotationFields extends AnnotationParser {
       generatedPropFactory.setUpdateTimestamp(prop);
     }
 
+    if (get(prop, HistoryExclude.class) != null) {
+      prop.setExcludedFromHistory(true);
+    }
+
     if (validationAnnotations) {
       NotNull notNull = get(prop, NotNull.class);
       if (notNull != null && isNotNullOnAllValidationGroups(notNull.groups())) {

src/main/java/com/avaje/ebeaninternal/server/deploy/parse/ReadAnnotations.java

@@ -8,7 +8,17 @@ import com.avaje.ebeaninternal.server.deploy.BeanDescriptorManager;
  */
 public class ReadAnnotations {
 
-	/**
+  /**
+   * Typically _with_history and when appended to the base table derives the name of
+   * the view that unions the base table with the history table to support asOf queries.
+   */
+  private final String asOfViewSuffix;
+
+  public ReadAnnotations(String asOfViewSuffix) {
+    this.asOfViewSuffix = asOfViewSuffix;
+  }
+
+  /**
 	 * Read the initial non-relationship annotations included Id and EmbeddedId.
 	 * <p>
 	 * We then have enough to create BeanTables which are used in readAssociations
@@ -18,7 +28,7 @@ public class ReadAnnotations {
     public void readInitial(DeployBeanInfo<?> info, boolean eagerFetchLobs){
 
     	try { 		
-    		new AnnotationClass(info).parse();
+    		new AnnotationClass(info, asOfViewSuffix).parse();
 	      new AnnotationFields(info, eagerFetchLobs).parse();
 	       
     	} catch (RuntimeException e){

src/main/java/com/avaje/ebeaninternal/server/expression/JunctionExpression.java

@@ -1,5 +1,6 @@
 package com.avaje.ebeaninternal.server.expression;
 
+import java.sql.Timestamp;
 import java.util.Collection;
 import java.util.List;
 import java.util.Map;
@@ -217,6 +218,11 @@ abstract class JunctionExpression<T> implements Junction<T>, SpiExpression, Expr
     throw new RuntimeException("filterMany not allowed on Junction expression list");
   }
 
+  @Override
+  public Query<T> asOf(Timestamp asOf) {
+    return exprList.asOf(asOf);
+  }
+
   @Override
   public Query<T> apply(PathProperties pathProperties) {
     return exprList.apply(pathProperties);

src/main/java/com/avaje/ebeaninternal/server/loadcontext/DLoadBeanContext.java

@@ -49,6 +49,7 @@ public class DLoadBeanContext extends DLoadBaseContext implements LoadBeanContex
     if (parent.isReadOnly() != null) {
       query.setReadOnly(parent.isReadOnly());
     }
+    query.asOf(parent.getAsOf());
     query.setParentNode(objectGraphNode);
     query.setLazyLoadProperty(lazyLoadProperty);
 

src/main/java/com/avaje/ebeaninternal/server/loadcontext/DLoadContext.java

@@ -13,6 +13,7 @@ import com.avaje.ebeaninternal.server.deploy.BeanPropertyAssocMany;
 import com.avaje.ebeaninternal.server.el.ElPropertyValue;
 import com.avaje.ebeaninternal.server.querydefn.OrmQueryProperties;
 
+import java.sql.Timestamp;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
@@ -30,7 +31,8 @@ public class DLoadContext implements LoadContext {
 	private final Map<String, DLoadManyContext> manyMap = new HashMap<String, DLoadManyContext>();
 	
 	private final DLoadBeanContext rootBeanContext;
-	
+
+  private final Timestamp asOf;
 	private final Boolean readOnly;
 	private final boolean excludeBeanCache;	
 	private final int defaultBatchSize;
@@ -56,6 +58,7 @@ public class DLoadContext implements LoadContext {
     this.rootDescriptor = request.getBeanDescriptor();
     
     SpiQuery<?> query = request.getQuery();
+    this.asOf = query.getAsOf();
     this.readOnly = query.isReadOnly();	  
 		this.excludeBeanCache = Boolean.FALSE.equals(query.isUseBeanCache());
 		this.useAutofetchManager = query.getAutoFetchManager() != null;		
@@ -211,8 +214,12 @@ public class DLoadContext implements LoadContext {
 	protected Boolean isReadOnly() {
 		return readOnly;
 	}
-	
-	public PersistenceContext getPersistenceContext() {
+
+  protected Timestamp getAsOf() {
+    return asOf;
+  }
+
+  public PersistenceContext getPersistenceContext() {
 		return persistenceContext;
 	}
 

src/main/java/com/avaje/ebeaninternal/server/loadcontext/DLoadManyContext.java

@@ -60,6 +60,8 @@ public class DLoadManyContext extends DLoadBaseContext implements LoadManyContex
   	if (parent.isReadOnly() != null){
   		query.setReadOnly(parent.isReadOnly());
   	}
+
+    query.asOf(parent.getAsOf());
 		query.setParentNode(objectGraphNode);
 		
 		if (queryProps != null){

src/main/java/com/avaje/ebeaninternal/server/query/CQueryBuilder.java

@@ -23,6 +23,8 @@ import com.avaje.ebeaninternal.server.querydefn.OrmQueryLimitRequest;
 
 import javax.persistence.PersistenceException;
 import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
 import java.util.Set;
 
 /**
@@ -43,14 +45,20 @@ public class CQueryBuilder implements Constants {
 
   private final boolean selectCountWithAlias;
 
+  private final Map<String,String> asOfTableMapping;
+
+  private final String asOfSysPeriod;
+
   private DatabasePlatform dbPlatform;
 
   /**
    * Create the SqlGenSelect.
    */
-  public CQueryBuilder(DatabasePlatform dbPlatform, Binder binder) {
+  public CQueryBuilder(DatabasePlatform dbPlatform, Binder binder, Map<String,String> asOfTableMapping, String asOfSysPeriod) {
 
     this.binder = binder;
+    this.asOfTableMapping = asOfTableMapping;
+    this.asOfSysPeriod = asOfSysPeriod;
     this.tableAliasPlaceHolder = dbPlatform.getTableAliasPlaceHolder();
     this.columnAliasPrefix = dbPlatform.getColumnAliasPrefix();
     this.sqlSelectBuilder = new RawSqlSelectClauseBuilder(dbPlatform, binder);
@@ -103,7 +111,8 @@ public class CQueryBuilder implements Constants {
     // use RawSql or generated Sql
     predicates.prepare(true);
 
-    SqlTree sqlTree = createSqlTree(request, predicates);
+    Map<String,String> asOfMap = query.isAsOfQuery() ? asOfTableMapping : null;
+    SqlTree sqlTree = createSqlTree(request, predicates, asOfMap);
     SqlLimitResponse s = buildSql(null, request, predicates, sqlTree);
     String sql = s.getSql();
 
@@ -155,7 +164,8 @@ public class CQueryBuilder implements Constants {
 
     predicates.prepare(true);
 
-    SqlTree sqlTree = createSqlTree(request, predicates);
+    Map<String,String> asOfMap = query.isAsOfQuery() ? asOfTableMapping : null;
+    SqlTree sqlTree = createSqlTree(request, predicates, asOfMap);
     SqlLimitResponse s = buildSql(sqlSelect, request, predicates, sqlTree);
     String sql = s.getSql();
     if (hasMany || query.isRawSql()) {
@@ -203,7 +213,14 @@ public class CQueryBuilder implements Constants {
     predicates.prepare(true);
 
     // Build the tree structure that represents the query.
-    SqlTree sqlTree = createSqlTree(request, predicates);
+    SpiQuery<T> query = request.getQuery();
+
+    Map<String,String> asOfMap = query.isAsOfQuery() ? asOfTableMapping : null;
+    SqlTree sqlTree = createSqlTree(request, predicates, asOfMap);
+    if (query.isAsOfQuery()) {
+      sqlTree.addAsOfTableAlias(query);
+    }
+
     SqlLimitResponse res = buildSql(null, request, predicates, sqlTree);
 
     boolean rawSql = request.isRawSql();
@@ -232,13 +249,13 @@ public class CQueryBuilder implements Constants {
    * order by clauses that are not already included for the select clause.
    * </p>
    */
-  private SqlTree createSqlTree(OrmQueryRequest<?> request, CQueryPredicates predicates) {
+  private SqlTree createSqlTree(OrmQueryRequest<?> request, CQueryPredicates predicates, Map<String,String> withHistoryTables) {
 
     if (request.isRawSql()) {
       return createRawSqlSqlTree(request, predicates);
     }
 
-    return new SqlTreeBuilder(tableAliasPlaceHolder, columnAliasPrefix, request, predicates).build();
+    return new SqlTreeBuilder(tableAliasPlaceHolder, columnAliasPrefix, request, predicates, withHistoryTables).build();
   }
 
   private SqlTree createRawSqlSqlTree(OrmQueryRequest<?> request, CQueryPredicates predicates) {
@@ -380,6 +397,7 @@ public class CQueryBuilder implements Constants {
     String dbFilterMany = predicates.getDbFilterMany();
     if (!isEmpty(dbFilterMany)) {
       if (!hasWhere) {
+        hasWhere = true;
         sb.append(" where ");
       } else {
         sb.append("and ");
@@ -387,7 +405,23 @@ public class CQueryBuilder implements Constants {
       sb.append(dbFilterMany);
     }
 
-    
+    List<String> asOfTableAlias = query.getAsOfTableAlias();
+    if (asOfTableAlias != null) {
+      // append the effective date predicates for each table alias
+      // that maps to a @History entity involved in this query
+      if (!hasWhere) {
+        sb.append(" where ");
+      } else {
+        sb.append("and ");
+      }
+      for (int i = 0; i < asOfTableAlias.size(); i++) {
+        if (i > 0) {
+          sb.append(" and ");
+        }
+        sb.append(dbPlatform.getAsOfPredicate(asOfTableAlias.get(i), asOfSysPeriod));
+      }
+    }
+
     if (dbOrderBy != null) {
       sb.append(" order by ").append(dbOrderBy);
     }

src/main/java/com/avaje/ebeaninternal/server/query/CQueryEngine.java

@@ -1,6 +1,7 @@
 package com.avaje.ebeaninternal.server.query;
 
 import java.sql.SQLException;
+import java.util.Map;
 
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -31,9 +32,9 @@ public class CQueryEngine {
 
   private final CQueryBuilder queryBuilder;
 
-  public CQueryEngine(DatabasePlatform dbPlatform, Binder binder) {
+  public CQueryEngine(DatabasePlatform dbPlatform, Binder binder, Map<String,String> asOfTableMapping, String asOfSysPeriod) {
     this.forwardOnlyHintOnFindIterate = dbPlatform.isForwardOnlyHintOnFindIterate();
-    this.queryBuilder = new CQueryBuilder(dbPlatform, binder);
+    this.queryBuilder = new CQueryBuilder(dbPlatform, binder, asOfTableMapping, asOfSysPeriod);
   }
 
   public <T> CQuery<T> buildQuery(OrmQueryRequest<T> request) {

src/main/java/com/avaje/ebeaninternal/server/query/CQueryPredicates.java

@@ -1,8 +1,10 @@
 package com.avaje.ebeaninternal.server.query;
 
 import java.sql.SQLException;
+import java.sql.Timestamp;
 import java.util.ArrayList;
 import java.util.HashSet;
+import java.util.List;
 import java.util.Set;
 
 import com.avaje.ebean.RawSql;
@@ -174,6 +176,17 @@ public class CQueryPredicates {
       }
     }
 
+    List<String> historyTableAlias = query.getAsOfTableAlias();
+    if (historyTableAlias != null) {
+      // bind the asAt value for each table alias
+      // there is one effective date predicate per table alias
+      Timestamp asOf = query.getAsOf();
+      bindLog.append(" asOf ").append(asOf);
+      for (int i = 0; i < historyTableAlias.size(); i++) {
+        binder.bindObject(dataBind, asOf);
+      }
+    }
+
     if (havingNamedParams != null) {
       // bind named parameters in having...
       bindLog.append(" havingNamed ");

src/main/java/com/avaje/ebeaninternal/server/query/DefaultDbSqlContext.java

@@ -1,14 +1,15 @@
 package com.avaje.ebeaninternal.server.query;
 
-import java.util.ArrayList;
-import java.util.HashSet;
-
 import com.avaje.ebeaninternal.server.deploy.BeanProperty;
 import com.avaje.ebeaninternal.server.deploy.DbSqlContext;
 import com.avaje.ebeaninternal.server.deploy.TableJoinColumn;
 import com.avaje.ebeaninternal.server.lib.util.StringHelper;
 import com.avaje.ebeaninternal.server.util.ArrayStack;
 
+import java.util.ArrayList;
+import java.util.HashSet;
+import java.util.Map;
+
 public class DefaultDbSqlContext implements DbSqlContext {
 
   private static final String COMMA = ", ";
@@ -45,25 +46,22 @@ public class DefaultDbSqlContext implements DbSqlContext {
 
   private ArrayList<BeanProperty> encryptedProps;
 
-  /**
-   * Construct for FROM clause (no column alias used).
-   */
-  public DefaultDbSqlContext(SqlTreeAlias alias, String tableAliasPlaceHolder) {
-    this.tableAliasPlaceHolder = tableAliasPlaceHolder;
-    this.columnAliasPrefix = null;
-    this.useColumnAlias = false;
-    this.alias = alias;
-  }
+  private final Map<String,String> asOfTableMap;
+
+  private final boolean asOfQuery;
 
   /**
    * Construct for SELECT clause (with column alias settings).
    */
   public DefaultDbSqlContext(SqlTreeAlias alias, String tableAliasPlaceHolder,
-      String columnAliasPrefix, boolean alwaysUseColumnAlias) {
+      String columnAliasPrefix, boolean alwaysUseColumnAlias, Map<String,String> asOfTableMap) {
+
     this.alias = alias;
     this.tableAliasPlaceHolder = tableAliasPlaceHolder;
     this.columnAliasPrefix = columnAliasPrefix;
     this.useColumnAlias = alwaysUseColumnAlias;
+    this.asOfTableMap = asOfTableMap;
+    this.asOfQuery = (asOfTableMap != null);
   }
 
   public void addEncryptedProp(BeanProperty p) {
@@ -108,7 +106,21 @@ public class DefaultDbSqlContext implements DbSqlContext {
 
     sb.append(" ");
     sb.append(type);
-    sb.append(" ").append(table).append(" ");
+    if (!asOfQuery) {
+      sb.append(" ").append(table).append(" ");
+
+    } else {
+      // check if there is an associated history table and if so
+      // use the unionAll view - we expect an additional predicate to match
+      String withHistoryTable = asOfTableMap.get(table);
+      if (withHistoryTable != null) {
+        // there is an associated history table and view so use that
+        sb.append(" ").append(withHistoryTable).append(" ");
+
+      } else {
+        sb.append(" ").append(table).append(" ");
+      }
+    }
     sb.append(a2);
     sb.append(" on ");
 
@@ -222,7 +234,7 @@ public class DefaultDbSqlContext implements DbSqlContext {
   public void appendColumn(String tableAlias, String column) {
     sb.append(COMMA);
 
-    if (column.indexOf("${}") > -1) {
+    if (column.contains("${}")) {
       // support DB functions such as lower() etc
       // with the use of secondary columns
       String x = StringHelper.replaceString(column, "${}", tableAlias);

src/main/java/com/avaje/ebeaninternal/server/query/SqlTree.java

@@ -1,5 +1,6 @@
 package com.avaje.ebeaninternal.server.query;
 
+import com.avaje.ebeaninternal.api.SpiQuery;
 import com.avaje.ebeaninternal.server.deploy.BeanProperty;
 import com.avaje.ebeaninternal.server.deploy.BeanPropertyAssocMany;
 import com.avaje.ebeaninternal.server.el.ElPropertyValue;
@@ -80,6 +81,13 @@ public class SqlTree {
     this.includes = null;
   }
 
+  /**
+   * Recurse through the tree adding an table alias' for @History entity beans.
+   */
+  public void addAsOfTableAlias(SpiQuery<?> query) {
+    rootNode.addAsOfTableAlias(query);
+  }
+
   /**
    * Build a select expression chain for RawSql.
    */

src/main/java/com/avaje/ebeaninternal/server/query/SqlTreeBuilder.java

@@ -98,7 +98,7 @@ public class SqlTreeBuilder {
    * to the root node.
    */
   public SqlTreeBuilder(String tableAliasPlaceHolder, String columnAliasPrefix,
-      OrmQueryRequest<?> request, CQueryPredicates predicates) {
+      OrmQueryRequest<?> request, CQueryPredicates predicates, Map<String,String> asOfTables) {
 
     this.rawSql = false;
     this.rawNoId = false;
@@ -112,7 +112,7 @@ public class SqlTreeBuilder {
 
     this.predicates = predicates;
     this.alias = new SqlTreeAlias(request.getQuery().getAlias()==null?request.getBeanDescriptor().getBaseTableAlias():request.getQuery().getAlias());
-    this.ctx = new DefaultDbSqlContext(alias, tableAliasPlaceHolder, columnAliasPrefix, !subQuery);
+    this.ctx = new DefaultDbSqlContext(alias, tableAliasPlaceHolder, columnAliasPrefix, !subQuery, asOfTables);
   }
 
   /**
@@ -265,7 +265,8 @@ public class SqlTreeBuilder {
       // Optional many property for lazy loading query
       BeanPropertyAssocMany<?> lazyLoadMany = (query == null) ? null : query.getLazyLoadForParentsProperty();
       boolean withId = !rawNoId && !subQuery && (query == null || !query.isDistinct());
-      return new SqlTreeNodeRoot(desc, props, myList, withId, includeJoin, lazyLoadMany);
+
+      return new SqlTreeNodeRoot(desc, props, myList, withId, includeJoin, lazyLoadMany, SpiQuery.TemporalMode.of(query));
 
     } else if (prop instanceof BeanPropertyAssocMany<?>) {
       return new SqlTreeNodeManyRoot(prefix, (BeanPropertyAssocMany<?>) prop, props, myList);

src/main/java/com/avaje/ebeaninternal/server/query/SqlTreeNode.java

@@ -1,6 +1,7 @@
 package com.avaje.ebeaninternal.server.query;
 
 import com.avaje.ebean.bean.EntityBean;
+import com.avaje.ebeaninternal.api.SpiQuery;
 import com.avaje.ebeaninternal.server.deploy.DbReadContext;
 import com.avaje.ebeaninternal.server.deploy.DbSqlContext;
 
@@ -32,6 +33,11 @@ public interface SqlTreeNode {
    */
   void appendWhere(DbSqlContext ctx);
 
+  /**
+   * Recurse through the tree adding an table alias' for @History entity beans.
+   */
+  void addAsOfTableAlias(SpiQuery<?> query);
+
   /**
    * Load the appropriate information from the SqlSelectReader.
    * <p>

src/main/java/com/avaje/ebeaninternal/server/query/SqlTreeNodeBean.java

@@ -9,6 +9,7 @@ import com.avaje.ebean.bean.BeanCollection;
 import com.avaje.ebean.bean.EntityBean;
 import com.avaje.ebean.bean.EntityBeanIntercept;
 import com.avaje.ebean.bean.PersistenceContext;
+import com.avaje.ebeaninternal.api.SpiQuery;
 import com.avaje.ebeaninternal.api.SpiQuery.Mode;
 import com.avaje.ebeaninternal.server.deploy.BeanDescriptor;
 import com.avaje.ebeaninternal.server.deploy.BeanProperty;
@@ -70,25 +71,36 @@ public class SqlTreeNodeBean implements SqlTreeNode {
   
   protected final BeanPropertyAssocMany<?> lazyLoadParent;
 
+  protected final SpiQuery.TemporalMode temporalMode;
+
   private final IdBinder lazyLoadParentIdBinder;
 
+  protected String baseTableAlias;
+
+  /**
+   * Table alias set if this bean node includes a join to a intersection
+   * table and that table has history support.
+   */
+  protected String intersectionAsOfTableAlias;
+
   public SqlTreeNodeBean(String prefix, BeanPropertyAssoc<?> beanProp, SqlTreeProperties props,
       List<SqlTreeNode> myChildren, boolean withId) {
 
-    this(prefix, beanProp, beanProp.getTargetDescriptor(), props, myChildren, withId, null);
+    this(prefix, beanProp, beanProp.getTargetDescriptor(), props, myChildren, withId, null, SpiQuery.TemporalMode.CURRENT);
   }
 
   /**
    * Create with the appropriate node.
    */
   public SqlTreeNodeBean(String prefix, BeanPropertyAssoc<?> beanProp, BeanDescriptor<?> desc,
-      SqlTreeProperties props, List<SqlTreeNode> myChildren, boolean withId,  BeanPropertyAssocMany<?> lazyLoadParent) {
+      SqlTreeProperties props, List<SqlTreeNode> myChildren, boolean withId,  BeanPropertyAssocMany<?> lazyLoadParent, SpiQuery.TemporalMode temporalMode) {
 
     this.lazyLoadParent = lazyLoadParent;
     this.lazyLoadParentIdBinder = (lazyLoadParent == null) ? null : lazyLoadParent.getBeanDescriptor().getIdBinder();
     this.prefix = prefix;
     this.nodeBeanProp = beanProp;
     this.desc = desc;
+    this.temporalMode = temporalMode;
     this.inheritInfo = desc.getInheritInfo();
     this.extraWhere = (beanProp == null) ? null : beanProp.getExtraWhere();
 
@@ -441,6 +453,8 @@ public class SqlTreeNodeBean implements SqlTreeNode {
     ctx.pushJoin(prefix);
     ctx.pushTableAlias(prefix);
 
+    baseTableAlias = ctx.getTableAlias(prefix);
+
     // join and return SqlJoinType to use for child joins
     joinType = appendFromBaseTable(ctx, joinType);
 
@@ -457,6 +471,21 @@ public class SqlTreeNodeBean implements SqlTreeNode {
     ctx.popJoin();
   }
 
+  public void addAsOfTableAlias(SpiQuery<?> query) {
+    // if history on this bean type add it's alias
+    // for each alias we add an effect date predicate
+    if (desc.isHistorySupport()) {
+      query.addAsOfTableAlias(baseTableAlias);
+    }
+    if (intersectionAsOfTableAlias != null) {
+      // adds the 'as of' predicate for this intersection table
+      query.addAsOfTableAlias(intersectionAsOfTableAlias);
+    }
+    for (int i = 0; i < children.length; i++) {
+      children[i].addAsOfTableAlias(query);
+    }
+  }
+
   /**
    * Join to base table for this node. This includes a join to the intersection
    * table if this is a ManyToMany node.
@@ -472,8 +501,12 @@ public class SqlTreeNodeBean implements SqlTreeNode {
         String parentAlias = ctx.getTableAlias(split[0]);
         String alias2 = alias + "z_";
 
+        // adding the additional join to the intersection table
         TableJoin manyToManyJoin = manyProp.getIntersectionTableJoin();
         manyToManyJoin.addJoin(joinType, parentAlias, alias2, ctx);
+        if (!manyProp.isExcludedFromHistory()) {
+          intersectionAsOfTableAlias = alias2;
+        }
 
         return nodeBeanProp.addJoin(joinType, alias2, alias, ctx);
       }

src/main/java/com/avaje/ebeaninternal/server/query/SqlTreeNodeExtraJoin.java

@@ -1,6 +1,7 @@
 package com.avaje.ebeaninternal.server.query;
 
 import com.avaje.ebean.bean.EntityBean;
+import com.avaje.ebeaninternal.api.SpiQuery;
 import com.avaje.ebeaninternal.server.deploy.BeanPropertyAssoc;
 import com.avaje.ebeaninternal.server.deploy.BeanPropertyAssocMany;
 import com.avaje.ebeaninternal.server.deploy.DbReadContext;
@@ -40,6 +41,11 @@ public class SqlTreeNodeExtraJoin implements SqlTreeNode {
     // nothing to add
   }
 
+  @Override
+  public void addAsOfTableAlias(SpiQuery<?> query) {
+    // nothing to do here
+  }
+
   /**
    * Return true if the extra join is a many join.
    * <p>

src/main/java/com/avaje/ebeaninternal/server/query/SqlTreeNodeManyRoot.java

@@ -13,7 +13,7 @@ public final class SqlTreeNodeManyRoot extends SqlTreeNodeBean {
   final BeanPropertyAssocMany<?> manyProp;
 
   public SqlTreeNodeManyRoot(String prefix, BeanPropertyAssocMany<?> prop, SqlTreeProperties props, List<SqlTreeNode> myList) {
-    super(prefix, prop, prop.getTargetDescriptor(), props, myList, true, null);
+    super(prefix, prop, prop.getTargetDescriptor(), props, myList, true, null, null);
     this.manyProp = prop;
   }
 

src/main/java/com/avaje/ebeaninternal/server/query/SqlTreeNodeManyWhereJoin.java

@@ -1,6 +1,7 @@
 package com.avaje.ebeaninternal.server.query;
 
 import com.avaje.ebean.bean.EntityBean;
+import com.avaje.ebeaninternal.api.SpiQuery;
 import com.avaje.ebeaninternal.server.deploy.BeanPropertyAssoc;
 import com.avaje.ebeaninternal.server.deploy.BeanPropertyAssocMany;
 import com.avaje.ebeaninternal.server.deploy.BeanPropertyAssocOne;
@@ -37,6 +38,11 @@ public class SqlTreeNodeManyWhereJoin implements SqlTreeNode {
     this.parentPrefix = split[0];
   }
 
+  @Override
+  public void addAsOfTableAlias(SpiQuery<?> query) {
+    // do nothing here ...
+  }
+
   /**
    * Append to the FROM clause for this node.
    */

src/main/java/com/avaje/ebeaninternal/server/query/SqlTreeNodeRoot.java

@@ -1,5 +1,6 @@
 package com.avaje.ebeaninternal.server.query;
 
+import com.avaje.ebeaninternal.api.SpiQuery;
 import com.avaje.ebeaninternal.server.deploy.BeanDescriptor;
 import com.avaje.ebeaninternal.server.deploy.BeanPropertyAssocMany;
 import com.avaje.ebeaninternal.server.deploy.DbSqlContext;
@@ -17,13 +18,14 @@ public final class SqlTreeNodeRoot extends SqlTreeNodeBean {
   /**
    * Specify for SqlSelect to include an Id property or not.
    */
-  public SqlTreeNodeRoot(BeanDescriptor<?> desc, SqlTreeProperties props, List<SqlTreeNode> myList, boolean withId, TableJoin includeJoin, BeanPropertyAssocMany<?> many) {
-    super(null, null, desc, props, myList, withId, many);
+  public SqlTreeNodeRoot(BeanDescriptor<?> desc, SqlTreeProperties props, List<SqlTreeNode> myList, boolean withId,
+                         TableJoin includeJoin, BeanPropertyAssocMany<?> many, SpiQuery.TemporalMode temporalMode) {
+    super(null, null, desc, props, myList, withId, many, temporalMode);
     this.includeJoin = includeJoin;
   }
 
   public SqlTreeNodeRoot(BeanDescriptor<?> desc, SqlTreeProperties props, List<SqlTreeNode> myList, boolean withId) {
-    super(null, null, desc, props, myList, withId, null);
+    super(null, null, desc, props, myList, withId, null, null);
     this.includeJoin = null;
   }
 
@@ -33,11 +35,11 @@ public final class SqlTreeNodeRoot extends SqlTreeNodeBean {
   @Override
   public SqlJoinType appendFromBaseTable(DbSqlContext ctx, SqlJoinType joinType) {
 
-    ctx.append(desc.getBaseTable());
-    ctx.append(" ").append(ctx.getTableAlias(null));
+    ctx.append(desc.getBaseTable(temporalMode));
+    ctx.append(" ").append(baseTableAlias);
 
     if (includeJoin != null) {
-      String a1 = ctx.getTableAlias(null);
+      String a1 = baseTableAlias;
       String a2 = "int_"; // unique alias for intersection join
       includeJoin.addJoin(joinType, a1, a2, ctx);
     }

src/main/java/com/avaje/ebeaninternal/server/querydefn/DefaultOrmQuery.java

@@ -1,5 +1,6 @@
 package com.avaje.ebeaninternal.server.querydefn;
 
+import java.sql.Timestamp;
 import java.util.ArrayList;
 import java.util.Iterator;
 import java.util.List;
@@ -12,7 +13,6 @@ import com.avaje.ebean.*;
 import com.avaje.ebean.OrderBy.Property;
 import com.avaje.ebean.bean.BeanCollectionTouched;
 import com.avaje.ebean.bean.CallStack;
-import com.avaje.ebean.bean.EntityBean;
 import com.avaje.ebean.bean.ObjectGraphNode;
 import com.avaje.ebean.bean.ObjectGraphOrigin;
 import com.avaje.ebean.bean.PersistenceContext;
@@ -153,6 +153,16 @@ public class DefaultOrmQuery<T> implements SpiQuery<T> {
 
   private DefaultExpressionList<T> havingExpressions;
 
+  /**
+   * The list of table alias associated with @History entity beans.
+   */
+  private List<String> asOfTableAlias;
+
+  /**
+   * Set for flashback style 'as of' query.
+   */
+  private Timestamp asOf;
+
   private int bufferFetchSizeHint;
 
   private boolean usageProfiling = true;
@@ -258,6 +268,30 @@ public class DefaultOrmQuery<T> implements SpiQuery<T> {
     return this;
   }
 
+  /**
+   * This table alias is for a @History entity involved in the query and as
+   * such we need to add a 'as of predicate' to the query using this alias.
+   */
+  public void addAsOfTableAlias(String tableAlias) {
+    if (asOfTableAlias == null) {
+      asOfTableAlias = new ArrayList<String>();
+    }
+    asOfTableAlias.add(tableAlias);
+  }
+
+  public List<String> getAsOfTableAlias() {
+    return asOfTableAlias;
+  }
+
+  public Timestamp getAsOf() {
+    return asOf;
+  }
+
+  public DefaultOrmQuery<T> asOf(Timestamp asOfDateTime) {
+    this.asOf = asOfDateTime;
+    return this;
+  }
+
   /**
    * Set the BeanDescriptor for the root type of this query.
    */
@@ -581,6 +615,15 @@ public class DefaultOrmQuery<T> implements SpiQuery<T> {
     return mode;
   }
 
+  @Override
+  public TemporalMode getTemporalMode() {
+    return asOf == null ? TemporalMode.CURRENT : TemporalMode.AS_OF;
+  }
+
+  public boolean isAsOfQuery() {
+    return asOf != null;
+  }
+
   public void setMode(Mode mode) {
     this.mode = mode;
   }
@@ -665,6 +708,7 @@ public class DefaultOrmQuery<T> implements SpiQuery<T> {
     builder.add(rawWhereClause).add(additionalWhere).add(additionalHaving);
     builder.add(mapKey);
     builder.add(id != null);
+    builder.add(asOf != null);
     builder.add(rawSql == null ? 0 : rawSql.queryHash());
     builder.add(includeTableJoin != null ? includeTableJoin.queryHash() : 0);
     builder.add(rootTableAlias);
@@ -735,6 +779,7 @@ public class DefaultOrmQuery<T> implements SpiQuery<T> {
     hc = hc * 31 + (whereExpressions == null ? 0 : whereExpressions.queryBindHash());
     hc = hc * 31 + (havingExpressions == null ? 0 : havingExpressions.queryBindHash());
     hc = hc * 31 + (bindParams == null ? 0 : bindParams.queryBindHash());
+    hc = hc * 31 + (asOf == null ? 0 : asOf.hashCode());
     return hc;
   }
 

src/main/java/com/avaje/ebeaninternal/util/DefaultExpressionList.java

@@ -1,5 +1,6 @@
 package com.avaje.ebeaninternal.util;
 
+import java.sql.Timestamp;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.List;
@@ -107,6 +108,11 @@ public class DefaultExpressionList<T> implements SpiExpressionList<T> {
     return query;
   }
 
+  @Override
+  public Query<T> asOf(Timestamp asOf) {
+    return query.asOf(asOf);
+  }
+
   @Override
   public ExpressionList<T> where() {
     return query.where();