Documentation added.

27 files changed, 848 insertions, 263 deletions

diff --git a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/db/CDODBUtil.java b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/db/CDODBUtil.java
index 7b28a913cb..5957710263 100644
--- a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/db/CDODBUtil.java
+++ b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/db/CDODBUtil.java
@@ -7,6 +7,9 @@
  * 
  * Contributors:
  *    Eike Stepper - initial API and implementation
+ *    Stefan Winkler - 271444: [DB] Multiple refactorings 
+ *      https://bugs.eclipse.org/bugs/show_bug.cgi?id=271444
+ *
  */
 package org.eclipse.emf.cdo.server.db;
 
@@ -135,6 +138,19 @@ public final class CDODBUtil
   }
 
   /**
+   * Execute update on the given prepared statement and handle common cases of return values.
+   * 
+   * @param stmt
+   *          the prepared statement
+   * @param exactlyOne
+   *          if <code>true</code>, the update count is checked to be <code>1</code>. Else the update result is only
+   *          checked so that the update was successful (i.e. result code != Statement.EXECUTE_FAILED).
+   * @return the update count / execution result as returned by {@link PreparedStatement#executeUpdate()}. Can be used
+   *         by the caller to perform more advanced checks.
+   * @throws SQLException
+   *           if {@link PreparedStatement#executeUpdate()} throws it.
+   * @throws IllegalStateException
+   *           if the check indicated by <code>excatlyOne</code> indicates an error.
    * @since 2.0
    */
   public static int sqlUpdate(PreparedStatement stmt, boolean exactlyOne) throws SQLException
@@ -155,29 +171,13 @@ public final class CDODBUtil
     return result;
   }
 
-  // public static CDODBStoreManager getStoreManager(IDBAdapter dbAdapter,
-  // DataSource dataSource)
-  // {
-  // CDODBStoreManager storeManager = new CDODBStoreManager(dbAdapter,
-  // dataSource);
-  // storeManager.initDatabase();
-  // return storeManager;
-  // }
-  //
-  // public static CDODBStoreManager getStoreManager()
-  // {
-  // Properties properties = OM.BUNDLE.getConfigProperties();
-  // String adapterName = properties.getProperty("store.adapterName", "derby-embedded");
-  // IDBAdapter dbAdapter = DBUtil.getDBAdapter(adapterName);
-  // DataSource dataSource = DBUtil.createDataSource(properties, "datasource");
-  // return getStoreManager(dbAdapter, dataSource);
-  // }
-
   /**
    * For debugging purposes ONLY!
    * 
+   * @deprecated Should only be used when debugging.
    * @since 2.0
    */
+  @Deprecated
   public static void sqlDump(Connection conn, String sql)
   {
     ContextTracer TRACER = new ContextTracer(OM.DEBUG, CDODBUtil.class);
@@ -246,8 +246,10 @@ public final class CDODBUtil
   /**
    * For debugging purposes ONLY!
    * 
+   * @deprecated Should only be used when debugging.
    * @since 2.0
    */
+  @Deprecated
   public static void sqlDump(IDBConnectionProvider connectionProvider, String sql)
   {
     Connection connection = connectionProvider.getConnection();
diff --git a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/db/IDBStore.java b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/db/IDBStore.java
index 9fd4f41452..5bc90d1bcc 100644
--- a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/db/IDBStore.java
+++ b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/db/IDBStore.java
@@ -7,6 +7,8 @@
  * 
  * Contributors:
  *    Eike Stepper - initial API and implementation
+ *    Stefan Winkler - 271444: [DB] Multiple refactorings 
+ *      https://bugs.eclipse.org/bugs/show_bug.cgi?id=271444  
  */
 package org.eclipse.emf.cdo.server.db;
 
@@ -50,6 +52,8 @@ public interface IDBStore extends IStore
   public IDBStoreAccessor getWriter(ITransaction transaction);
 
   /**
+   * Get the meta data manager associated with this DBStore.
+   * 
    * @since 2.0
    */
   public IMetaDataManager getMetaDataManager();
diff --git a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/db/IMetaDataManager.java b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/db/IMetaDataManager.java
index ac76a09eb6..0e4e7a31fe 100644
--- a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/db/IMetaDataManager.java
+++ b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/db/IMetaDataManager.java
@@ -7,7 +7,7 @@
  * 
  * Contributors:
  *    Eike Stepper - initial API and implementation
- *    Stefan Winkler - major refactoring
+ *    Stefan Winkler - 271444: [DB] Multiple refactorings https://bugs.eclipse.org/bugs/show_bug.cgi?id=271444  
  */
 package org.eclipse.emf.cdo.server.db;
 
@@ -31,31 +31,66 @@ import java.util.Collection;
 public interface IMetaDataManager
 {
   /**
+   * Returns the meta ID of the given {@link EModelElement}. <code> getMetaID(getMetaInstance(x))</code> yields
+   * <code>x</code>
+   * 
+   * @param modelElement
+   *          the element
+   * @return the corresponding ID
    * @since 2.0
    */
   public long getMetaID(EModelElement modelElement);
 
   /**
+   * Returns the {@link EModelElement} referred to by the given ID. <code> getMetaInstance(getMetaID(m))</code> yields
+   * <code>m</code>
+   * 
    * @since 2.0
    */
   public EModelElement getMetaInstance(long id);
 
   /**
+   * Loads a package unit from the database.
+   * 
+   * @param connection
+   *          the DB connection to read from.
+   * @param packageUnit
+   *          the package unit to load.
+   * @return the loaded package unit.
    * @since 2.0
    */
   public EPackage[] loadPackageUnit(Connection connection, InternalCDOPackageUnit packageUnit);
 
-  /**
+/**
+   * Reads information about package units present in the database.
+   * @param connection the DB connection to read from.
+   * @return a collection of package unit information records which can be 
+   *   passed to {@link IMetaDataManager#loadPackageUnit(Connection, InternalCDOPackageUnit))
+   *   in order to read the EPackage.
+   *   
    * @since 2.0
    */
   public Collection<InternalCDOPackageUnit> readPackageUnits(Connection connection);
 
   /**
+   * Write package units to the database.
+   * 
+   * @param connection
+   *          the DB connection to write to.
+   * @param packageUnits
+   *          the package units to write.
+   * @param monitor
+   *          the monitor to indicate progress.
    * @since 2.0
    */
   public void writePackageUnits(Connection connection, InternalCDOPackageUnit[] packageUnits, OMMonitor monitor);
 
   /**
+   * Get the DB type associated with the given {@link EClassifier}.
+   * 
+   * @param eType
+   *          the type to look up.
+   * @return the {@link DBType} of the given {@link EClassifier}.
    * @since 2.0
    */
   public DBType getDBType(EClassifier eType);
diff --git a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/db/IObjectTypeCache.java b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/db/IObjectTypeCache.java
index 5b9bdbff31..b7f86154c5 100644
--- a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/db/IObjectTypeCache.java
+++ b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/db/IObjectTypeCache.java
@@ -7,6 +7,7 @@
  * 
  * Contributors:
  *    Eike Stepper - initial API and implementation
+ *    Stefan Winkler - 271444: [DB] Multiple refactorings https://bugs.eclipse.org/bugs/show_bug.cgi?id=271444  
  */
 package org.eclipse.emf.cdo.server.db;
 
@@ -38,6 +39,11 @@ public interface IObjectTypeCache
   public void removeObjectType(IDBStoreAccessor accessor, CDOID id);
 
   /**
+   * Return the maximum object id managed by this cache.
+   * 
+   * @param connection
+   *          the DB connection to use.
+   * @return the maximum object id.
    * @since 2.0
    */
   public long getMaxId(Connection connection);
diff --git a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/db/mapping/IAuditSupport.java b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/db/mapping/IAuditSupport.java
index 7a6311f9a5..15bf3cc983 100644
--- a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/db/mapping/IAuditSupport.java
+++ b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/db/mapping/IAuditSupport.java
@@ -7,7 +7,7 @@
  * 
  * Contributors:
  *    Eike Stepper - initial API and implementation
- *    Stefan Winkler - major refactoring
+ *    Stefan Winkler - 271444: [DB] Multiple refactorings https://bugs.eclipse.org/bugs/show_bug.cgi?id=271444  
  */
 package org.eclipse.emf.cdo.server.db.mapping;
 
@@ -15,17 +15,57 @@ import org.eclipse.emf.cdo.server.db.IDBStoreAccessor;
 import org.eclipse.emf.cdo.spi.common.revision.InternalCDORevision;
 
 /**
+ * Interface which complements {@link IClassMapping} with methods to facilitate 
+ * audit support.
+ * 
+ * @see {@link IMappingStrategy#hasAuditSupport()
+ * 
  * @author Eike Stepper
  * @author Stefan Winkler
+ * 
  * @since 2.0
  */
 public interface IAuditSupport
 {
 
-  boolean readRevisionByVersion(IDBStoreAccessor dbStoreAccessor, InternalCDORevision revision, int version,
-      int referenceChunk);
+  /**
+   * Read a specific version of a revision. If this method returns <code>true</code> it is guaranteed that
+   * <code>revision.getVersion() == version</code>
+   * 
+   * @param dbStoreAccessor
+   *          the accessor to use.
+   * @param revision
+   *          the revision object into which the data should be read. The revision has to be have its ID set to the
+   *          requested object's ID. The version is ignored, as the version parameter is used to determine the version
+   *          to be read.
+   * @param version
+   *          the version which should be read.
+   * @param listChunk
+   *          the chunk size to read attribute lists.
+   * @return <code>true</code>, if the revision has been found and read correctly. <code>false</code> if the revision
+   *         could not be found. In this case, the content of <code>revision</code> is undefined.
+   */
+  public boolean readRevisionByVersion(IDBStoreAccessor dbStoreAccessor, InternalCDORevision revision, int version,
+      int listChunk);
 
-  boolean readRevisionByTime(IDBStoreAccessor dbStoreAccessor, InternalCDORevision revision, long timeStamp,
-      int referenceChunk);
+  /**
+   * Read a specific past version of a revision. If this method returns <code>true</code> it is guaranteed that
+   * <code>revision.getCreated() <= timeStamp && (getRevised() == 0 || getRevised() >= timeStamp))</code>
+   * 
+   * @param dbStoreAccessor
+   *          the accessor to use.
+   * @param revision
+   *          the revision object into which the data should be read. The revision has to be have its ID set to the
+   *          requested object's ID. The version is ignored, as the version parameter is used to determine the version
+   *          to be read.
+   * @param timeStamp
+   *          the timeStamp which should be used to determine the revision's version.
+   * @param listChunk
+   *          the chunk size to read attribute lists.
+   * @return <code>true</code>, if the revision has been found and read correctly. <code>false</code> if the revision
+   *         could not be found. In this case, the content of <code>revision</code> is undefined.
+   */
+  public boolean readRevisionByTime(IDBStoreAccessor dbStoreAccessor, InternalCDORevision revision, long timeStamp,
+      int listChunk);
 
 }
diff --git a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/db/mapping/IClassMapping.java b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/db/mapping/IClassMapping.java
index 2a27b70083..2367cf8add 100644
--- a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/db/mapping/IClassMapping.java
+++ b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/db/mapping/IClassMapping.java
@@ -7,15 +7,17 @@
  * 
  * Contributors:
  *    Eike Stepper - initial API and implementation
- *    Stefan Winkler - major refactoring
+ *    Stefan Winkler - 271444: [DB] Multiple refactorings https://bugs.eclipse.org/bugs/show_bug.cgi?id=271444  
  */
 package org.eclipse.emf.cdo.server.db.mapping;
 
 import org.eclipse.emf.cdo.common.id.CDOID;
+import org.eclipse.emf.cdo.common.revision.CDORevision;
 import org.eclipse.emf.cdo.server.db.IDBStoreAccessor;
 import org.eclipse.emf.cdo.spi.common.revision.InternalCDORevision;
 
 import org.eclipse.net4j.db.ddl.IDBTable;
+import org.eclipse.net4j.util.ImplementationError;
 import org.eclipse.net4j.util.om.monitor.OMMonitor;
 
 import org.eclipse.emf.ecore.EStructuralFeature;
@@ -24,26 +26,103 @@ import java.sql.PreparedStatement;
 import java.util.Collection;
 
 /**
+ * Basic interface for class mappings.
+ * 
  * @author Eike Stepper
  * @author Stefan Winkler
  * @since 2.0
  */
 public interface IClassMapping
 {
+  /**
+   * Returns all DB tables which are used by this class and all its contained features.
+   * 
+   * @return a collection of all tables of this class and all its contained features.
+   */
+  public Collection<IDBTable> getDBTables();
 
-  void detachObject(IDBStoreAccessor dbStoreAccessor, CDOID id, long revised, OMMonitor monitor);
+  /**
+   * Get the mapping of the many-valued feature.
+   * 
+   * @param feature
+   *          the feature for which the mapping should be returned. <code>feature.isMany()</code> has to be
+   *          <code>true</code>.
+   * @return the list mapping corresponding to the feature.
+   */
+  public IListMapping getListMapping(EStructuralFeature feature);
 
-  void writeRevision(IDBStoreAccessor dbStoreAccessor, InternalCDORevision revision, OMMonitor monitor);
+  /**
+   * Read the current version of a revision.
+   * 
+   * @param dbStoreAccessor
+   *          the accessor to use.
+   * @param revision
+   *          the revision object into which the data should be read. The revision has to be have its ID set to the
+   *          requested object's ID. The version is ignored, as the version parameter is used to determine the version
+   *          to be read.
+   * @param listChunk
+   *          the chunk size to read attribute lists.
+   * @return <code>true</code>, if the revision has been found and read correctly. <code>false</code> if the revision
+   *         could not be found. In this case, the content of <code>revision</code> is undefined.
+   */
+  public boolean readRevision(IDBStoreAccessor dbStoreAccessor, InternalCDORevision revision, int listChunk);
 
-  boolean readRevision(IDBStoreAccessor dbStoreAccessor, InternalCDORevision revision, int referenceChunk);
+  /**
+   * Write the revision data to the database.
+   * 
+   * @param dbStoreAccessor
+   *          the accessor to use.
+   * @param revision
+   *          the revision to write.
+   * @param monitor
+   *          the monitor to indicate progress.
+   */
+  public void writeRevision(IDBStoreAccessor dbStoreAccessor, InternalCDORevision revision, OMMonitor monitor);
 
-  Collection<IDBTable> getDBTables();
+  /**
+   * Removes an object from the database. In the case of auditing support the object is just marked as revised, else it
+   * it permanently deleted.
+   * 
+   * @param dbStoreAccessor
+   *          the accessor to use.
+   * @param id
+   *          the ID of the object to remove.
+   * @param revised
+   *          the timeStamp when this object became detached.
+   * @param monitor
+   *          the monitor to indicate progress.
+   */
+  public void detachObject(IDBStoreAccessor dbStoreAccessor, CDOID id, long revised, OMMonitor monitor);
 
-  PreparedStatement createObjectIdStatement(IDBStoreAccessor accessor);
+  /**
+   * Create a prepared statement which returns all IDs of instances of the corresponding class.
+   * 
+   * @param accessor
+   *          the accessor to use to create the statement
+   * @return the prepared statement ready to be executed using <code>result.executeQuery()</code>.
+   */
+  public PreparedStatement createObjectIdStatement(IDBStoreAccessor accessor);
 
-  PreparedStatement createResourceQueryStatement(IDBStoreAccessor accessor, CDOID folderId, String name,
+  /**
+   * Create a prepared statement which returns all IDs of instances of the corresponding class.
+   * 
+   * @param accessor
+   *          the accessor to use to create the statement
+   * @param folderId
+   *          the ID of the containing folder. <code>0</code> means none.
+   * @param name
+   *          the name of the resource node to look up
+   * @param exactMatch
+   *          if <code>true</code>, <code>name</code> must match exactly, otherwise all resource nodes starting with
+   *          <code>name</code> are returned.
+   * @param timeStamp
+   *          a timestamp in the past if past versions should be looked up. In case of no audit support, this must be
+   *          {@link CDORevision#UNSPECIFIED_DATE}.
+   * @return the prepared statement ready to be executed using <code>result.executeQuery()</code>.
+   * @throws ImplementationError
+   *           if called on a mapping which does not map an <code>EClass instanceof CDOResourceNode</code>.
+   */
+  public PreparedStatement createResourceQueryStatement(IDBStoreAccessor accessor, CDOID folderId, String name,
       boolean exactMatch, long timeStamp);
 
-  IListMapping getListMapping(EStructuralFeature feature);
-
 }
diff --git a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/db/mapping/IDeltaSupport.java b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/db/mapping/IDeltaSupport.java
index 072dd0a61a..4e73d84015 100644
--- a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/db/mapping/IDeltaSupport.java
+++ b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/db/mapping/IDeltaSupport.java
@@ -1,5 +1,5 @@
 /**
- * Copyright (c) 2004 - 2009 Eike Stepper (Berlin, Germany) and others.
+ * Copyright (c) 2004 - 2009 Eike Stepper (Berlin, Germany) and others. 
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -7,7 +7,7 @@
  * 
  * Contributors:
  *    Eike Stepper - initial API and implementation
- *    Stefan Winkler - major refactoring
+ *    Stefan Winkler - 271444: [DB] Multiple refactorings https://bugs.eclipse.org/bugs/show_bug.cgi?id=271444  
  */
 package org.eclipse.emf.cdo.server.db.mapping;
 
@@ -17,6 +17,11 @@ import org.eclipse.emf.cdo.spi.common.revision.InternalCDORevisionDelta;
 import org.eclipse.net4j.util.om.monitor.OMMonitor;
 
 /**
+ * Interface which complements {@link IClassMapping} with methods to facilitate 
+ * revision delta support.
+ * 
+ * @see {@link IMappingStrategy#hasDeltaSupport()
+ * 
  * @author Eike Stepper
  * @author Stefan Winkler
  * @since 2.0
@@ -24,7 +29,18 @@ import org.eclipse.net4j.util.om.monitor.OMMonitor;
 public interface IDeltaSupport
 {
 
-  void writeRevisionDelta(IDBStoreAccessor dbStoreAccessor, InternalCDORevisionDelta delta, long created,
+  /**
+   * Write a revision delta.
+   * 
+   * @param dbStoreAccessor
+   *          the accessor to use.
+   * @param delta
+   *          the delta to write.
+   * @param created
+   *          the creation timestamp of the new version
+   * @param monitor
+   *          the monitor to report progress.
+   */
+  public void writeRevisionDelta(IDBStoreAccessor dbStoreAccessor, InternalCDORevisionDelta delta, long created,
       OMMonitor monitor);
-
 }
diff --git a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/db/mapping/IListMapping.java b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/db/mapping/IListMapping.java
index 53f3274c02..c26ce2b807 100644
--- a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/db/mapping/IListMapping.java
+++ b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/db/mapping/IListMapping.java
@@ -12,6 +12,7 @@
 package org.eclipse.emf.cdo.server.db.mapping;
 
 import org.eclipse.emf.cdo.common.id.CDOID;
+import org.eclipse.emf.cdo.common.revision.CDORevision;
 import org.eclipse.emf.cdo.server.IStoreChunkReader.Chunk;
 import org.eclipse.emf.cdo.server.db.IDBStoreAccessor;
 import org.eclipse.emf.cdo.server.db.IDBStoreChunkReader;
@@ -25,26 +26,74 @@ import java.util.Collection;
 import java.util.List;
 
 /**
+ * Interface for mapping features with <code>isMany() == true</code>.
+ * 
  * @author Eike Stepper
  * @author Stefan Winkler
  * @since 2.0
  */
 public interface IListMapping
 {
+  /**
+   * Return the mapped feature.
+   * 
+   * @return the mapped feature.
+   */
+  public EStructuralFeature getFeature();
 
-  void writeValues(IDBStoreAccessor accessor, InternalCDORevision revision);
-
-  void readValues(IDBStoreAccessor accessor, InternalCDORevision revision, int referenceChunk);
+  /**
+   * Returns all DB tables which are used by this feature.
+   * 
+   * @return a collection of all tables of this feature.
+   */
+  public Collection<IDBTable> getDBTables();
 
-  void readChunks(IDBStoreChunkReader dbStoreChunkReader, List<Chunk> chunks, String string);
+  /**
+   * Write a complete list of values to the database.
+   * 
+   * @param accessor
+   *          the accessor to use.
+   * @param revision
+   *          the revision containing the list to be written.
+   */
+  public void writeValues(IDBStoreAccessor accessor, InternalCDORevision revision);
 
-  Collection<IDBTable> getDBTables();
+  /**
+   * Read the list size and the complete list or the first part of it.
+   * 
+   * @param accessor
+   *          the accessor to use.
+   * @param revision
+   *          the revision into which the list values should be read.
+   * @param listChunk
+   *          indicating the lazy loading behavior: {@link CDORevision#UNCHUNKED} means that the whole list should be
+   *          read. Else, if <code>listChunk >= 0</code>, the list is filled with
+   *          {@link InternalCDORevision#UNINITIALIZED} and only the first <code>listChunk</code> values are read.
+   */
+  public void readValues(IDBStoreAccessor accessor, InternalCDORevision revision, int listChunk);
 
-  EStructuralFeature getFeature();
+  /**
+   * Used to load-on-demand chunks of a list.
+   * 
+   * @param dbStoreChunkReader
+   *          the chunkReader to use
+   * @param chunks
+   *          the chunks to read
+   * @param where
+   *          the where-clause to use in order to read the chunks.
+   */
+  public void readChunks(IDBStoreChunkReader dbStoreChunkReader, List<Chunk> chunks, String where);
 
   /**
    * Hook with which a list mapping is notified that a containing object has been revised. Can be implemented in order
    * to clean up lists of revised objects.
+   * 
+   * @param accessor
+   *          the accessor to use.
+   * @param id
+   *          the ID of the object which has been revised.
+   * @param revised
+   *          the timestamp at which the object was revised.
    */
-  void objectRevised(IDBStoreAccessor accessor, CDOID id, long revised);
+  public void objectRevised(IDBStoreAccessor accessor, CDOID id, long revised);
 }
diff --git a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/db/mapping/IListMappingDeltaSupport.java b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/db/mapping/IListMappingDeltaSupport.java
index 5bdcd16f2b..823c760d07 100644
--- a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/db/mapping/IListMappingDeltaSupport.java
+++ b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/db/mapping/IListMappingDeltaSupport.java
@@ -1,5 +1,5 @@
 /**
- * Copyright (c) 2004 - 2009 Eike Stepper (Berlin, Germany) and others.
+ * Copyright (c) 2004 - 2009 Eike Stepper (Berlin, Germany) and others. 
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -7,7 +7,7 @@
  * 
  * Contributors:
  *    Eike Stepper - initial API and implementation
- *    Stefan Winkler - major refactoring
+ *    Stefan Winkler - 271444: [DB] Multiple refactorings https://bugs.eclipse.org/bugs/show_bug.cgi?id=271444  
  */
 package org.eclipse.emf.cdo.server.db.mapping;
 
@@ -15,19 +15,84 @@ import org.eclipse.emf.cdo.common.id.CDOID;
 import org.eclipse.emf.cdo.server.db.IDBStoreAccessor;
 
 /**
+ * Interface to complement {@link IListMapping} in order to provide list delta processing support.
+ * 
  * @author Eike Stepper
  * @author Stefan Winkler
  * @since 2.0
  */
 public interface IListMappingDeltaSupport
 {
-  void removeListItem(IDBStoreAccessor accessor, CDOID id, int newVersion, int index);
-
+  /**
+   * Insert a list item at a specified position.
+   * 
+   * @param accessor
+   *          the accessor to use
+   * @param id
+   *          the id of the revision to insert the value
+   * @param newVersion
+   *          the new version of the revision after the value is inserted.
+   * @param index
+   *          the position at which the value should be inserted.
+   * @param value
+   *          the value to insert.
+   */
   void insertListItem(IDBStoreAccessor accessor, CDOID id, int newVersion, int index, Object value);
 
-  void clearList(IDBStoreAccessor accessor, CDOID id);
-
+  /**
+   * Set a value at a specified position to the given value.
+   * 
+   * @param accessor
+   *          the accessor to use
+   * @param id
+   *          the id of the revision to set the value
+   * @param newVersion
+   *          the new version of the revision after the value is set.
+   * @param index
+   *          the position at which the value should be set.
+   * @param value
+   *          the value to be set.
+   */
   void setListItem(IDBStoreAccessor accessor, CDOID id, int newVersion, int index, Object value);
 
+  /**
+   * Move a list item from one position to another. Indices between both positions are updated so that the list remains
+   * consistent.
+   * 
+   * @param accessor
+   *          the accessor to use
+   * @param id
+   *          the id of the revision in which to move the item
+   * @param newVersion
+   *          the new version of the revision after the item is moved.
+   * @param oldPosition
+   *          the old position of the item.
+   * @param newPosition
+   *          the new position of the item.
+   */
   void moveListItem(IDBStoreAccessor accessor, CDOID id, int newVersion, int oldPosition, int newPosition);
+
+  /**
+   * Remove a list item from a specified a position.
+   * 
+   * @param accessor
+   *          the accessor to use
+   * @param id
+   *          the id of the revision from which to remove the item
+   * @param newVersion
+   *          the new version of the revision after the item is removed.
+   * @param index
+   *          the index of the item to be removed.
+   */
+  void removeListItem(IDBStoreAccessor accessor, CDOID id, int newVersion, int index);
+
+  /**
+   * Clear a list of a given revision.
+   * 
+   * @param accessor
+   *          the accessor to use
+   * @param id
+   *          the id of the revision from which to remove all items
+   */
+  void clearList(IDBStoreAccessor accessor, CDOID id);
 }
diff --git a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/db/mapping/IMappingStrategy.java b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/db/mapping/IMappingStrategy.java
index 0b056ca739..2ffd5aca26 100644
--- a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/db/mapping/IMappingStrategy.java
+++ b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/db/mapping/IMappingStrategy.java
@@ -1,5 +1,5 @@
 /**
- * Copyright (c) 2004 - 2009 Eike Stepper (Berlin, Germany) and others.
+ * Copyright (c) 2004 - 2009 Eike Stepper (Berlin, Germany) and others. 
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -7,7 +7,7 @@
  * 
  * Contributors:
  *    Eike Stepper - initial API and implementation
- *    Stefan Winkler - major refactoring
+ *    Stefan Winkler - 271444: [DB] Multiple refactorings https://bugs.eclipse.org/bugs/show_bug.cgi?id=271444  
  */
 package org.eclipse.emf.cdo.server.db.mapping;
 
@@ -16,6 +16,7 @@ import org.eclipse.emf.cdo.common.model.CDOClassifierRef;
 import org.eclipse.emf.cdo.server.IStoreAccessor.QueryResourcesContext;
 import org.eclipse.emf.cdo.server.db.IDBStore;
 import org.eclipse.emf.cdo.server.db.IDBStoreAccessor;
+import org.eclipse.emf.cdo.server.internal.db.DBStore;
 import org.eclipse.emf.cdo.spi.common.model.InternalCDOPackageUnit;
 
 import org.eclipse.net4j.db.IDBAdapter;
@@ -30,6 +31,12 @@ import java.sql.Connection;
 import java.util.Map;
 
 /**
+ * The mapping strategy acts as a connection between the DBStore and the database management (and OR-mapping) classes.
+ * The {@link DBStore} uses methods of this interface to create and lookup mappings (or mappers, as they could also be
+ * named as such) and to get properties and informations about the mappings used. The mapping classes (e.g., instances
+ * of IClassMapping and IListMapping) also use this class as a central point of information and as a resource of common
+ * functionalities.
+ * 
  * @author Eike Stepper
  * @author Stefan Winkler
  * @since 2.0
@@ -65,39 +72,161 @@ public interface IMappingStrategy
    */
   public static final String PROP_FORCE_NAMES_WITH_ID = "forceNamesWithID";
 
-  public static final String PROP_TO_MANY_REFERENCE_MAPPING = "toManyReferenceMapping";
-
-  public static final String PROP_TO_ONE_REFERENCE_MAPPING = "toOneReferenceMapping";
-
+  /**
+   * @return the store, this MappingStrategy instance belongs to.
+   */
   public IDBStore getStore();
 
+  /**
+   * Set the store to which this MappingStrategy instance belongs. Should only be called by the {@link DBStore}, and
+   * only once to initialize the connection between {@link DBStore} and mapping strategy.
+   * 
+   * @param dbStore
+   *          the DBStore instance to which this MappingStrategy instance belongs.
+   */
   public void setStore(IDBStore dbStore);
 
+  /**
+   * Factory for value mappings of single-valued attributes.
+   * 
+   * @param feature
+   *          the feature for which a mapping should be created. It must hold <code>feature.isMany() == false</code>.
+   * @return the mapping created.
+   */
   public ITypeMapping createValueMapping(EStructuralFeature feature);
 
+  /**
+   * Factory for value mappings of multi-valued-attributes.
+   * 
+   * @param containingClass
+   *          the class containing the feature.
+   * @param feature
+   *          the feature for which a mapping should be created. It must hold <code>feature.isMany() == true</code>.
+   * @return
+   */
   public IListMapping createListMapping(EClass containingClass, EStructuralFeature feature);
 
-  public String getTableName(ENamedElement eClass);
+  /**
+   * Create a suitable table name which can be used to map the given element. Should only be called by mapping classes.
+   * 
+   * @param element
+   *          the element for which the name should be created. It must hold:
+   *          <code>element instanceof EClass || element instanceof EPackage</code>.
+   * @return the created table name. It is guaranteed that the table name is compatible with the chosen database.
+   */
+  public String getTableName(ENamedElement element);
 
+  /**
+   * Create a suitable table name which can be used to map the given element. Should only be called by mapping classes.
+   * Should only be called by mapping classes.
+   * 
+   * @param containingClass
+   *          the class containeng the feature.
+   * @param feature
+   *          the feature for which the table name should be created.
+   * @return the created table name. It is guaranteed that the table name is compatible with the chosen database.
+   */
   public String getTableName(EClass containingClass, EStructuralFeature feature);
 
+  /**
+   * Create a suitable column name which can be used to map the given element. Should only be called by mapping classes.
+   * 
+   * @param feature
+   *          the feature for which the column name should be created.
+   * @return the created column name. It is guaranteed that the name is compatible with the chosen database.
+   */
   public String getFieldName(EStructuralFeature feature);
 
+  /**
+   * Create and initialize the mapping infrastructure for the given packages. Should be called from the DBStore or the
+   * DBStoreAccessor.
+   * 
+   * @param connection
+   *          the connection to use.
+   * @param packageUnits
+   *          the packages whose elements should be mapped.
+   * @param monitor
+   *          the monitor to report progress.
+   */
   public void createMapping(Connection connection, InternalCDOPackageUnit[] packageUnits, OMMonitor monitor);
 
+  /**
+   * Look up an existing class mapping for the given class. Before this method is called, the class mapping must have
+   * been initialized by calling {@link #createMapping(Connection, InternalCDOPackageUnit[], OMMonitor)} on its
+   * containing package.
+   * 
+   * @param eClass
+   *          the class to look up.
+   * @return the class mapping.
+   */
   public IClassMapping getClassMapping(EClass eClass);
 
+  /**
+   * Query if this mapping supports revision deltas. <br>
+   * If this method returns <code>true</code>, it is guaranteed that all class mappings returned by
+   * {@link #getClassMapping(EClass)} implement {@link IDeltaSupport}.
+   * 
+   * @return <code>true</code> if revision deltas are supported, <code>false</code> else.
+   */
   public boolean hasDeltaSupport();
 
-  public void queryResources(IDBStoreAccessor dbStoreAccessor, QueryResourcesContext context);
-
+  /**
+   * Query if this mapping supports audits. <br>
+   * If this method returns <code>true</code>, it is guaranteed that all class mappings returned by
+   * {@link #getClassMapping(EClass)} implement {@link IAuditSupport}.
+   * 
+   * @return <code>true</code> if audits are supported, <code>false</code> else.
+   */
   public boolean hasAuditSupport();
 
+  /**
+   * Execute a resource query.
+   * 
+   * @param dbStoreAccessor
+   *          the accessor to use.
+   * @param context
+   *          the context from which the query parameters are read and to which the result is written.
+   */
+  public void queryResources(IDBStoreAccessor dbStoreAccessor, QueryResourcesContext context);
+
+  /**
+   * Read the type (i.e. class) of the object referred to by a given ID.
+   * 
+   * @param dbStoreAccessor
+   *          the accessor to use to look up the type.
+   * @param id
+   *          the ID of the object for which the type is to be determined.
+   * @return the type of the object.
+   */
   public CDOClassifierRef readObjectType(IDBStoreAccessor dbStoreAccessor, CDOID id);
 
+  /**
+   * Get an iterator over all instances of objects in the store.
+   * 
+   * @param dbStoreAccessor
+   *          the accessor to use.
+   * @return the iterator.
+   */
   public CloseableIterator<CDOID> readObjectIDs(IDBStoreAccessor dbStoreAccessor);
 
+  /**
+   * Return the maximum object id used in the store. This is used by the DBStore if a previous crash is discovered
+   * during the startup process. Should only be called by the DBStore and only during startup.
+   * 
+   * @param dbAdapter
+   *          the dbAdapter to use to access the database
+   * @param connection
+   *          the connection to use to access the database
+   * @return the maximum object id used in the store.
+   */
   public long repairAfterCrash(IDBAdapter dbAdapter, Connection connection);
 
+  /**
+   * Set configuration properties for this mapping strategy. Should only be called by the factory creating the mapping
+   * strategy instance.
+   * 
+   * @param properties
+   *          the configuration properties to set.
+   */
   public void setProperties(Map<String, String> properties);
 }
diff --git a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/db/mapping/ITypeMapping.java b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/db/mapping/ITypeMapping.java
index 59adc24f54..c16756cc06 100644
--- a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/db/mapping/ITypeMapping.java
+++ b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/db/mapping/ITypeMapping.java
@@ -23,25 +23,98 @@ import java.sql.ResultSet;
 import java.sql.SQLException;
 
 /**
+ * Mapping of single values to and from the database.
+ * 
  * @author Eike Stepper
  * @author Stefan Winkler
  * @since 2.0
  */
 public interface ITypeMapping
 {
-  public void setValueFromRevision(PreparedStatement stmt, int index, InternalCDORevision value) throws SQLException;
-
-  public void setValue(PreparedStatement stmt, int index, Object value) throws SQLException;
-
-  public void readValueToRevision(ResultSet resultSet, int i, InternalCDORevision revision) throws SQLException;
+  /**
+   * @return The feature which is associated with this mapping.
+   */
+  public EStructuralFeature getFeature();
 
-  public Object readValue(ResultSet resultSet, int i) throws SQLException;
+  /**
+   * @return The db field which is associated with this mapping.
+   */
+  public IDBField getField();
 
+  /**
+   * Creates the DBField and adds it to the given table. The name of the DBField is derived from the feature.
+   * 
+   * @param table
+   *          the table to add this field to.
+   */
   public void createDBField(IDBTable table);
 
+  /**
+   * Creates the DBField and adds it to the given table. The name of the DBField is explicitly determined by the
+   * corresponding parameter.
+   * 
+   * @param table
+   *          the table to add this field to.
+   * @param fieldName
+   *          the name for the DBField.
+   */
   public void createDBField(IDBTable table, String fieldName);
 
-  public IDBField getField();
+  /**
+   * Set the given value to the JDBC {@link PreparedStatement} using an appropriate <code>setXxx</code> method.
+   * 
+   * @param stmt
+   *          the prepared statement to set the value
+   * @param index
+   *          the index to use for the <code>setXxx</code> method.
+   * @param value
+   *          the value to set.
+   * @throws SQLException
+   *           if the <code>setXxx</code> throws it.
+   */
+  public void setValue(PreparedStatement stmt, int index, Object value) throws SQLException;
+
+  /**
+   * Set a value of the given revision to the JDBC {@link PreparedStatement} using an appropriate <code>setXxx</code>
+   * method. The feature from which the value is taken is determined by {@link #getFeature()}.
+   * 
+   * @param stmt
+   *          the prepared statement to set the value
+   * @param index
+   *          the index to use for the <code>setXxx</code> method.
+   * @param revision
+   *          the revision to get the value to set from.
+   * @throws SQLException
+   *           if the <code>setXxx</code> throws it.
+   */
+  public void setValueFromRevision(PreparedStatement stmt, int index, InternalCDORevision value) throws SQLException;
+
+  /**
+   * Read a value from a {@link ResultSet} and convert it from the DB to the CDO representation.
+   * 
+   * @param resultSet
+   *          the result set to read from
+   * @param i
+   *          the column index in the result set to read from
+   * @return the read value
+   * @throws SQLException
+   *           if reading the value throws an SQLException
+   */
+  public Object readValue(ResultSet resultSet, int i) throws SQLException;
+
+  /**
+   * Read a value from a {@link ResultSet}, convert it from the DB to the CDO representation and set it to the feature
+   * of the revision. The feature is determined by getFeature()
+   * 
+   * @param resultSet
+   *          the result set to read from
+   * @param i
+   *          the column index in the result set to read from
+   * @param revision
+   *          the revision to which the value should be set.
+   * @throws SQLException
+   *           if reading the value throws an SQLException
+   */
+  public void readValueToRevision(ResultSet resultSet, int i, InternalCDORevision revision) throws SQLException;
 
-  public EStructuralFeature getFeature();
 }
diff --git a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/CDODBSchema.java b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/CDODBSchema.java
index 7e55b96d7f..a772fe809c 100644
--- a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/CDODBSchema.java
+++ b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/CDODBSchema.java
@@ -1,5 +1,5 @@
 /**
- * Copyright (c) 2004 - 2009 Eike Stepper (Berlin, Germany) and others.
+ * Copyright (c) 2004 - 2009 Eike Stepper (Berlin, Germany) and others. 
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -7,6 +7,8 @@
  * 
  * Contributors:
  *    Eike Stepper - initial API and implementation
+ *    Stefan Winkler - 271444: [DB] Multiple refactorings https://bugs.eclipse.org/bugs/show_bug.cgi?id=271444
+ *
  */
 package org.eclipse.emf.cdo.server.internal.db;
 
@@ -120,17 +122,17 @@ public class CDODBSchema extends DBSchema
   public static final String ATTRIBUTES_FEATURE = "cdo_feature";
 
   /**
-   * Field names of reference tables
+   * Field names of list tables
    */
-  public static final String REFERENCES_FEATURE = "cdo_feature";
+  public static final String LIST_FEATURE = "cdo_feature";
 
-  public static final String FEATURE_REVISION_ID = "cdo_source";
+  public static final String LIST_REVISION_ID = "cdo_source";
 
-  public static final String FEATURE_REVISION_VERSION = "cdo_version";
+  public static final String LIST_REVISION_VERSION = "cdo_version";
 
-  public static final String FEATURE_IDX = "cdo_idx";
+  public static final String LIST_IDX = "cdo_idx";
 
-  public static final String FEATURE_TARGET = "cdo_target";
+  public static final String LIST_VALUE = "cdo_value";
 
   private CDODBSchema()
   {
diff --git a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/DBStore.java b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/DBStore.java
index 705373c83c..68e1524ed4 100644
--- a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/DBStore.java
+++ b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/DBStore.java
@@ -7,7 +7,8 @@
  * 
  * Contributors:
  *    Eike Stepper - initial API and implementation
- *    Stefan Winkler - https://bugs.eclipse.org/bugs/show_bug.cgi?id=259402    
+ *    Stefan Winkler - https://bugs.eclipse.org/bugs/show_bug.cgi?id=259402
+ *    Stefan Winkler - 271444: [DB] Multiple refactorings https://bugs.eclipse.org/bugs/show_bug.cgi?id=271444      
  */
 package org.eclipse.emf.cdo.server.internal.db;
 
@@ -29,7 +30,6 @@ import org.eclipse.net4j.db.ddl.IDBSchema;
 import org.eclipse.net4j.db.ddl.IDBTable;
 import org.eclipse.net4j.spi.db.DBSchema;
 import org.eclipse.net4j.util.ReflectUtil.ExcludeFromDump;
-import org.eclipse.net4j.util.lifecycle.ILifecycle;
 import org.eclipse.net4j.util.lifecycle.LifecycleUtil;
 import org.eclipse.net4j.util.om.monitor.ProgressDistributor;
 
@@ -40,7 +40,7 @@ import java.text.MessageFormat;
 import java.util.Set;
 
 /**
- * @author Eike Stepper TODO: factor out type map and meta stuff into MetadataManager
+ * @author Eike Stepper
  */
 public class DBStore extends LongIDStore implements IDBStore
 {
@@ -80,7 +80,7 @@ public class DBStore extends LongIDStore implements IDBStore
   @ExcludeFromDump
   private transient StoreAccessorPool writerPool = new StoreAccessorPool(this, null);
 
-  private IMetaDataManager metaDataManager;
+  private transient IMetaDataManager metaDataManager;
 
   public DBStore()
   {
@@ -212,7 +212,7 @@ public class DBStore extends LongIDStore implements IDBStore
     super.doActivate();
 
     metaDataManager = new MetaDataManager(this);
-    ((ILifecycle)metaDataManager).activate();
+    LifecycleUtil.activate(metaDataManager);
 
     Connection connection = getConnection();
     LifecycleUtil.activate(mappingStrategy);
@@ -301,7 +301,7 @@ public class DBStore extends LongIDStore implements IDBStore
   {
     Connection connection = null;
 
-    ((ILifecycle)metaDataManager).deactivate();
+    LifecycleUtil.deactivate(metaDataManager);
     metaDataManager = null;
 
     try
diff --git a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/DBStoreAccessor.java b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/DBStoreAccessor.java
index e6d1d7fafa..68c7ec9940 100644
--- a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/DBStoreAccessor.java
+++ b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/DBStoreAccessor.java
@@ -1,5 +1,5 @@
 /**
- * Copyright (c) 2004 - 2009 Eike Stepper (Berlin, Germany) and others.
+ * Copyright (c) 2004 - 2009 Eike Stepper (Berlin, Germany) and others. 
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -8,6 +8,7 @@
  * Contributors:
  *    Eike Stepper - initial API and implementation
  *    Stefan Winkler - https://bugs.eclipse.org/bugs/show_bug.cgi?id=259402
+ *    Stefan Winkler - 271444: [DB] Multiple refactorings https://bugs.eclipse.org/bugs/show_bug.cgi?id=271444
  */
 package org.eclipse.emf.cdo.server.internal.db;
 
@@ -94,15 +95,11 @@ public class DBStoreAccessor extends LongIDStoreAccessor implements IDBStoreAcce
     return (DBStore)super.getStore();
   }
 
-  /** TODO: check how to handle */
   public DBStoreChunkReader createChunkReader(InternalCDORevision revision, EStructuralFeature feature)
   {
     return new DBStoreChunkReader(this, revision, feature);
   }
 
-  /**
-   * TODO caching?
-   */
   public CloseableIterator<CDOID> readObjectIDs()
   {
     if (TRACER.isEnabled())
@@ -113,9 +110,6 @@ public class DBStoreAccessor extends LongIDStoreAccessor implements IDBStoreAcce
     return getStore().getMappingStrategy().readObjectIDs(this);
   }
 
-  /**
-   * TODO caching?
-   */
   public CDOClassifierRef readObjectType(CDOID id)
   {
     if (TRACER.isEnabled())
@@ -128,7 +122,8 @@ public class DBStoreAccessor extends LongIDStoreAccessor implements IDBStoreAcce
 
   protected EClass getObjectType(CDOID id)
   {
-    // TODO Replace calls to getObjectType by optimized calls to RevisionManager.getObjectType (cache!)
+    // TODO (taken over from old implementation:) Replace calls to getObjectType by optimized calls to
+    // RevisionManager.getObjectType (cache!)
     CDOClassifierRef type = readObjectType(id);
     if (type == null)
     {
@@ -140,7 +135,7 @@ public class DBStoreAccessor extends LongIDStoreAccessor implements IDBStoreAcce
     return (EClass)type.resolve(packageRegistry);
   }
 
-  public InternalCDORevision readRevision(CDOID id, int referenceChunk, AdditionalRevisionCache cache)
+  public InternalCDORevision readRevision(CDOID id, int listChunk, AdditionalRevisionCache cache)
   {
     if (TRACER.isEnabled())
     {
@@ -157,7 +152,7 @@ public class DBStoreAccessor extends LongIDStoreAccessor implements IDBStoreAcce
 
     IMappingStrategy mappingStrategy = getStore().getMappingStrategy();
     IClassMapping mapping = mappingStrategy.getClassMapping(eClass);
-    if (mapping.readRevision(this, revision, referenceChunk))
+    if (mapping.readRevision(this, revision, listChunk))
     {
       return revision;
     }
@@ -166,8 +161,7 @@ public class DBStoreAccessor extends LongIDStoreAccessor implements IDBStoreAcce
     return null;
   }
 
-  public InternalCDORevision readRevisionByTime(CDOID id, int referenceChunk, AdditionalRevisionCache cache,
-      long timeStamp)
+  public InternalCDORevision readRevisionByTime(CDOID id, int listChunk, AdditionalRevisionCache cache, long timeStamp)
   {
     IMappingStrategy mappingStrategy = getStore().getMappingStrategy();
 
@@ -185,7 +179,7 @@ public class DBStoreAccessor extends LongIDStoreAccessor implements IDBStoreAcce
     InternalCDORevision revision = (InternalCDORevision)CDORevisionUtil.create(eClass, id);
 
     IAuditSupport mapping = (IAuditSupport)mappingStrategy.getClassMapping(eClass);
-    if (mapping.readRevisionByTime(this, revision, timeStamp, referenceChunk))
+    if (mapping.readRevisionByTime(this, revision, timeStamp, listChunk))
     {
       return revision;
     }
@@ -194,8 +188,7 @@ public class DBStoreAccessor extends LongIDStoreAccessor implements IDBStoreAcce
     return null;
   }
 
-  public InternalCDORevision readRevisionByVersion(CDOID id, int referenceChunk, AdditionalRevisionCache cache,
-      int version)
+  public InternalCDORevision readRevisionByVersion(CDOID id, int listChunk, AdditionalRevisionCache cache, int version)
   {
     IMappingStrategy mappingStrategy = getStore().getMappingStrategy();
 
@@ -213,7 +206,7 @@ public class DBStoreAccessor extends LongIDStoreAccessor implements IDBStoreAcce
       }
 
       // if audit support is present, just use the audit method
-      success = ((IAuditSupport)mapping).readRevisionByVersion(this, revision, version, referenceChunk);
+      success = ((IAuditSupport)mapping).readRevisionByVersion(this, revision, version, listChunk);
     }
     else
     {
@@ -228,7 +221,7 @@ public class DBStoreAccessor extends LongIDStoreAccessor implements IDBStoreAcce
         TRACER.format("Selecting current base revision: {0}", id);
       }
 
-      success = mapping.readRevision(this, revision, referenceChunk);
+      success = mapping.readRevision(this, revision, listChunk);
 
       if (success && revision.getVersion() != version)
       {
diff --git a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/DBStoreChunkReader.java b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/DBStoreChunkReader.java
index d05d1570bb..1de3985e2d 100644
--- a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/DBStoreChunkReader.java
+++ b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/DBStoreChunkReader.java
@@ -49,7 +49,7 @@ public class DBStoreChunkReader extends StoreChunkReader implements IDBStoreChun
   {
     super.addSimpleChunk(index);
     builder.append(" AND ");
-    builder.append(CDODBSchema.FEATURE_IDX);
+    builder.append(CDODBSchema.LIST_IDX);
     builder.append("=");
     builder.append(index);
   }
@@ -59,7 +59,7 @@ public class DBStoreChunkReader extends StoreChunkReader implements IDBStoreChun
   {
     super.addRangedChunk(fromIndex, toIndex);
     builder.append(" AND ");
-    builder.append(CDODBSchema.FEATURE_IDX);
+    builder.append(CDODBSchema.LIST_IDX);
     builder.append(" BETWEEN ");
     builder.append(fromIndex);
     builder.append(" AND ");
diff --git a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/DBStoreFactory.java b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/DBStoreFactory.java
index b2759fc713..7112195c4a 100644
--- a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/DBStoreFactory.java
+++ b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/DBStoreFactory.java
@@ -7,6 +7,7 @@
  * 
  * Contributors:
  *    Eike Stepper - initial API and implementation
+ *    Stefan Winkler - 271444: [DB] Multiple refactorings https://bugs.eclipse.org/bugs/show_bug.cgi?id=271444  
  */
 package org.eclipse.emf.cdo.server.internal.db;
 
diff --git a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/MetaDataManager.java b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/MetaDataManager.java
index a7722f2c6e..9cc7b5508e 100644
--- a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/MetaDataManager.java
+++ b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/MetaDataManager.java
@@ -7,7 +7,7 @@
  * 
  * Contributors:
  *    Eike Stepper - initial API and implementation
- *    Stefan Winkler - major refactoring
+ *    Stefan Winkler - 271444: [DB] Multiple refactorings https://bugs.eclipse.org/bugs/show_bug.cgi?id=271444  
  */
 package org.eclipse.emf.cdo.server.internal.db;
 
diff --git a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/AbstractMappingStrategy.java b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/AbstractMappingStrategy.java
index d6238f31a7..903f61abe7 100644
--- a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/AbstractMappingStrategy.java
+++ b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/AbstractMappingStrategy.java
@@ -8,6 +8,7 @@
  * Contributors:
  *    Eike Stepper - initial API and implementation
  *    Stefan Winkler - major refactoring
+ *    Stefan Winkler - 271444: [DB] Multiple refactorings https://bugs.eclipse.org/bugs/show_bug.cgi?id=271444  
  */
 package org.eclipse.emf.cdo.server.internal.db.mapping;
 
@@ -56,12 +57,16 @@ import java.util.Map;
 import java.util.Set;
 
 /**
+ * This abstract base class implements those methods which are most likely common to most mapping strategies. It can be
+ * used to derive custom mapping strategy implementation.
+ * 
  * @author Eike Stepper
  * @author Stefan Winkler
  * @since 2.0
  */
 public abstract class AbstractMappingStrategy extends Lifecycle implements IMappingStrategy
 {
+  // --------- database name generation strings --------------
   protected static final String NAME_SEPARATOR = "_";
 
   protected static final String TYPE_PREFIX_FEATURE = "F";
@@ -74,7 +79,7 @@ public abstract class AbstractMappingStrategy extends Lifecycle implements IMapp
 
   // private static final ContextTracer TRACER = new ContextTracer(OM.DEBUG, AbstractMappingStrategy.class);
 
-  private IDBStore store;
+  private IDBStore store = null;
 
   private Map<String, String> properties;
 
@@ -141,6 +146,7 @@ public abstract class AbstractMappingStrategy extends Lifecycle implements IMapp
 
   public final void setStore(IDBStore dbStore)
   {
+    checkInactive();
     store = dbStore;
   }
 
@@ -197,7 +203,6 @@ public abstract class AbstractMappingStrategy extends Lifecycle implements IMapp
         currentStatement = null;
       }
     };
-
   };
 
   public abstract CDOClassifierRef readObjectType(IDBStoreAccessor dbStoreAccessor, CDOID id);
@@ -365,7 +370,13 @@ public abstract class AbstractMappingStrategy extends Lifecycle implements IMapp
 
   public final IClassMapping getClassMapping(EClass eClass)
   {
-    return classMappings.get(eClass);
+    IClassMapping result = classMappings.get(eClass);
+    if (result != null)
+    {
+      return result;
+    }
+
+    throw new ImplementationError("Class mapping not found for " + eClass.toString());
   }
 
   public ITypeMapping createValueMapping(EStructuralFeature feature)
@@ -426,6 +437,7 @@ public abstract class AbstractMappingStrategy extends Lifecycle implements IMapp
 
   public final IListMapping createListMapping(EClass containingClass, EStructuralFeature feature)
   {
+    checkArg(feature.isMany(), "Only many-valued features allowed.");
     IListMapping mapping = doCreateListMapping(containingClass, feature);
     return mapping;
   }
diff --git a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/TypeMapping.java b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/TypeMapping.java
index f423cffc49..d2f301d427 100644
--- a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/TypeMapping.java
+++ b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/TypeMapping.java
@@ -7,7 +7,7 @@
  * 
  * Contributors:
  *    Eike Stepper - initial API and implementation
- *    Stefan Winkler - major refactoring
+ *    Stefan Winkler - 271444: [DB] Multiple refactorings https://bugs.eclipse.org/bugs/show_bug.cgi?id=271444
  */
 package org.eclipse.emf.cdo.server.internal.db.mapping;
 
@@ -32,6 +32,9 @@ import java.sql.Timestamp;
 import java.util.Date;
 
 /**
+ * This is a default implementation for the {@link ITypeMapping} interface which provides default behavor for all common
+ * types.
+ * 
  * @author Eike Stepper
  * @author Stefan Winkler
  */
@@ -43,6 +46,14 @@ public abstract class TypeMapping implements ITypeMapping
 
   private IDBField field;
 
+  /**
+   * Create a new type mapping
+   * 
+   * @param mappingStrategy
+   *          the associated mapping strategy.
+   * @param feature
+   *          the feature to be mapped.
+   */
   public TypeMapping(IMappingStrategy mappingStrategy, EStructuralFeature feature)
   {
     this.mappingStrategy = mappingStrategy;
diff --git a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/horizontal/AbstractHorizontalClassMapping.java b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/horizontal/AbstractHorizontalClassMapping.java
index a78b702115..aa11d0a37a 100644
--- a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/horizontal/AbstractHorizontalClassMapping.java
+++ b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/horizontal/AbstractHorizontalClassMapping.java
@@ -7,7 +7,7 @@
  * 
  * Contributors:
  *    Eike Stepper - initial API and implementation
- *    Stefan Winkler - major refactoring
+ *    Stefan Winkler - 271444: [DB] Multiple refactorings https://bugs.eclipse.org/bugs/show_bug.cgi?id=271444  
  */
 package org.eclipse.emf.cdo.server.internal.db.mapping.horizontal;
 
@@ -191,11 +191,11 @@ public abstract class AbstractHorizontalClassMapping implements IClassMapping
     }
   }
 
-  protected final void readLists(IDBStoreAccessor accessor, InternalCDORevision revision, int referenceChunk)
+  protected final void readLists(IDBStoreAccessor accessor, InternalCDORevision revision, int listChunk)
   {
     for (IListMapping listMapping : listMappings)
     {
-      listMapping.readValues(accessor, revision, referenceChunk);
+      listMapping.readValues(accessor, revision, listChunk);
     }
   }
 
@@ -264,7 +264,8 @@ public abstract class AbstractHorizontalClassMapping implements IClassMapping
         return mapping;
       }
     }
-    return null;
+
+    throw new IllegalArgumentException("List mapping for feature " + feature + " does not exist.");
   }
 
   protected final IDBTable getTable()
diff --git a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/horizontal/AbstractHorizontalMappingStrategy.java b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/horizontal/AbstractHorizontalMappingStrategy.java
index 8579cad2d8..1097c65c62 100644
--- a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/horizontal/AbstractHorizontalMappingStrategy.java
+++ b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/horizontal/AbstractHorizontalMappingStrategy.java
@@ -7,7 +7,7 @@
  * 
  * Contributors:
  *    Eike Stepper - initial API and implementation
- *    Stefan Winkler - major refactoring
+ *    Stefan Winkler - 271444: [DB] Multiple refactorings https://bugs.eclipse.org/bugs/show_bug.cgi?id=271444  
  */
 package org.eclipse.emf.cdo.server.internal.db.mapping.horizontal;
 
@@ -15,6 +15,7 @@ import org.eclipse.emf.cdo.common.id.CDOID;
 import org.eclipse.emf.cdo.common.id.CDOIDUtil;
 import org.eclipse.emf.cdo.common.model.CDOClassifierRef;
 import org.eclipse.emf.cdo.common.revision.CDORevision;
+import org.eclipse.emf.cdo.eresource.CDOResourceNode;
 import org.eclipse.emf.cdo.eresource.EresourcePackage;
 import org.eclipse.emf.cdo.server.IStoreAccessor.QueryResourcesContext;
 import org.eclipse.emf.cdo.server.db.IDBStoreAccessor;
@@ -38,6 +39,13 @@ import java.sql.SQLException;
 import java.util.Collection;
 
 /**
+ * * This abstract base class refines {@link AbstractMappingStrategy} by implementing aspects common to horizontal
+ * mapping strategies -- namely:
+ * <ul>
+ * <li>object type cache (table cdo_objects)
+ * <li>resource query handling
+ * </ul>
+ * 
  * @author Eike Stepper
  * @author Stefan Winkler
  * @since 2.0
@@ -46,6 +54,9 @@ public abstract class AbstractHorizontalMappingStrategy extends AbstractMappingS
 {
   private static final ContextTracer TRACER = new ContextTracer(OM.DEBUG, AbstractHorizontalMappingStrategy.class);
 
+  /**
+   * The associated object type cache.
+   */
   private IObjectTypeCache objectTypeCache;
 
   @Override
@@ -62,7 +73,7 @@ public abstract class AbstractHorizontalMappingStrategy extends AbstractMappingS
   @Override
   public long repairAfterCrash(IDBAdapter dbAdapter, Connection connection)
   {
-    return objectTypeCache.getMaxId(connection);
+    return objectTypeCache.getMaxId(connection) + 1;
   }
 
   @Override
@@ -100,6 +111,7 @@ public abstract class AbstractHorizontalMappingStrategy extends AbstractMappingS
   @Override
   public void queryResources(IDBStoreAccessor dbStoreAccessor, QueryResourcesContext context)
   {
+    // only support timestamp in audit mode
     if (context.getTimeStamp() != CDORevision.UNSPECIFIED_DATE && !hasAuditSupport())
     {
       throw new UnsupportedOperationException("Mapping Strategy does not support audits.");
@@ -107,7 +119,12 @@ public abstract class AbstractHorizontalMappingStrategy extends AbstractMappingS
 
     EresourcePackage resourcesPackage = EresourcePackage.eINSTANCE;
 
-    if (queryResources(dbStoreAccessor, getClassMapping(resourcesPackage.getCDOResourceFolder()), context))
+    // first query folders
+    boolean shallContinue = queryResources(dbStoreAccessor, getClassMapping(resourcesPackage.getCDOResourceFolder()),
+        context);
+
+    // not enough results? -> query resources
+    if (shallContinue)
     {
       queryResources(dbStoreAccessor, getClassMapping(resourcesPackage.getCDOResource()), context);
     }
@@ -117,8 +134,14 @@ public abstract class AbstractHorizontalMappingStrategy extends AbstractMappingS
    * This is an intermediate implementation. It should be changed after classmappings support a general way to implement
    * queries ...
    * 
-   * @return true if result context is not yet full and query should continue false, if result context is full and query
-   *         should stop.
+   * @param accessor
+   *          the accessor to use.
+   * @param classMapping
+   *          the class mapping of a class instanceof {@link CDOResourceNode} which should be queried.
+   * @param context
+   *          the query context containing the parameters and the result.
+   * @return <code>true</code> if result context is not yet full and query should continue false, if result context is
+   *         full and query should stop.
    */
   private boolean queryResources(IDBStoreAccessor accessor, IClassMapping classMapping, QueryResourcesContext context)
   {
diff --git a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/horizontal/AbstractListTableMapping.java b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/horizontal/AbstractListTableMapping.java
index c98acee320..8dd6bc41e7 100644
--- a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/horizontal/AbstractListTableMapping.java
+++ b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/horizontal/AbstractListTableMapping.java
@@ -1,5 +1,5 @@
 /**
- *  Copyright (c) 2004 - 2009 Eike Stepper (Berlin, Germany) and others.
+ *  Copyright (c) 2004 - 2009 Eike Stepper (Berlin, Germany) and others. 
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -7,7 +7,7 @@
  * 
  * Contributors:
  *    Eike Stepper - initial API and implementation
- *    Stefan Winkler - major refactoring
+ *    Stefan Winkler - 271444: [DB] Multiple refactorings https://bugs.eclipse.org/bugs/show_bug.cgi?id=271444  
  */
 package org.eclipse.emf.cdo.server.internal.db.mapping.horizontal;
 
@@ -44,6 +44,8 @@ import java.util.Collection;
 import java.util.List;
 
 /**
+ * This abstract base class provides basic behavior needed for mapping many-valued attributes to tables.
+ * 
  * @author Eike Stepper
  * @author Stefan Winkler
  * @since 2.0
@@ -52,14 +54,27 @@ public abstract class AbstractListTableMapping implements IListMapping
 {
   private static final ContextTracer TRACER = new ContextTracer(OM.DEBUG, AbstractListTableMapping.class);
 
+  /**
+   * The feature for this mapping.
+   */
   private EStructuralFeature feature;
 
+  /**
+   * The table of this mapping.
+   */
   private IDBTable table;
 
+  /**
+   * The type mapping for the value field.
+   */
   private ITypeMapping typeMapping;
 
+  /**
+   * The associated mapping strategy.
+   */
   private IMappingStrategy mappingStrategy;
 
+  // --------- SQL strings - see initSqlStrings() -----------------
   private String sqlSelectChunksPrefix;
 
   private String sqlOrderByIndex;
@@ -68,6 +83,8 @@ public abstract class AbstractListTableMapping implements IListMapping
 
   private EClass containingClass;
 
+  private String sqlGetListLastIndex;
+
   public AbstractListTableMapping(IMappingStrategy mappingStrategy, EClass eClass, EStructuralFeature feature)
   {
     this.mappingStrategy = mappingStrategy;
@@ -93,11 +110,11 @@ public abstract class AbstractListTableMapping implements IListMapping
     }
 
     // add field for list index
-    IDBField idxField = table.addField(CDODBSchema.FEATURE_IDX, DBType.INTEGER);
+    IDBField idxField = table.addField(CDODBSchema.LIST_IDX, DBType.INTEGER);
 
     // add field for value
     typeMapping = mappingStrategy.createValueMapping(feature);
-    typeMapping.createDBField(table, CDODBSchema.FEATURE_TARGET);
+    typeMapping.createDBField(table, CDODBSchema.LIST_VALUE);
 
     // add table indexes
     table.addIndex(Type.NON_UNIQUE, dbFields);
@@ -121,7 +138,7 @@ public abstract class AbstractListTableMapping implements IListMapping
     // ---------------- SELECT to read chunks ----------------------------
     StringBuilder builder = new StringBuilder();
     builder.append("SELECT ");
-    builder.append(CDODBSchema.FEATURE_TARGET);
+    builder.append(CDODBSchema.LIST_VALUE);
     builder.append(" FROM ");
     builder.append(tableName);
     builder.append(" WHERE ");
@@ -143,7 +160,32 @@ public abstract class AbstractListTableMapping implements IListMapping
 
     sqlSelectChunksPrefix = builder.toString();
 
-    sqlOrderByIndex = " ORDER BY " + CDODBSchema.FEATURE_IDX;
+    sqlOrderByIndex = " ORDER BY " + CDODBSchema.LIST_IDX;
+
+    // ----------------- count list size --------------------------
+
+    builder = new StringBuilder("SELECT max(");
+    builder.append(CDODBSchema.LIST_IDX);
+    builder.append(") FROM ");
+    builder.append(tableName);
+    builder.append(" WHERE ");
+
+    for (int i = 0; i < fields.length; i++)
+    {
+      builder.append(fields[i].getName());
+      if (i + 1 < fields.length)
+      {
+        // more to come
+        builder.append("= ? AND ");
+      }
+      else
+      {
+        // last one
+        builder.append("= ? ");
+      }
+    }
+
+    sqlGetListLastIndex = builder.toString();
 
     // ----------------- INSERT - reference entry -----------------
     builder = new StringBuilder("INSERT INTO ");
@@ -177,10 +219,26 @@ public abstract class AbstractListTableMapping implements IListMapping
     return typeMapping;
   }
 
-  public void readValues(IDBStoreAccessor accessor, InternalCDORevision revision, int referenceChunk)
+  public void readValues(IDBStoreAccessor accessor, InternalCDORevision revision, int listChunk)
   {
 
     MoveableList<Object> list = revision.getList(getFeature());
+    int listSize = 0;
+
+    if (listChunk != CDORevision.UNCHUNKED)
+    {
+      listSize = getListLastIndex(accessor, revision);
+      if (listSize == -1)
+      {
+        // list is empty - take shortcut
+        return;
+      }
+      else
+      {
+        // subtract amount of items we are going to read now
+        listSize -= listChunk;
+      }
+    }
 
     if (TRACER.isEnabled())
     {
@@ -206,7 +264,7 @@ public abstract class AbstractListTableMapping implements IListMapping
 
       resultSet = pstmt.executeQuery();
 
-      while ((referenceChunk == CDORevision.UNCHUNKED || --referenceChunk >= 0) && resultSet.next())
+      while ((listChunk == CDORevision.UNCHUNKED || --listChunk >= 0) && resultSet.next())
       {
         Object value = typeMapping.readValue(resultSet, 1);
         if (TRACER.isEnabled())
@@ -216,21 +274,75 @@ public abstract class AbstractListTableMapping implements IListMapping
         list.add(value);
       }
 
-      // TODO Optimize this?
-      while (resultSet.next())
+      while (listSize-- > 0)
       {
+        list.add(InternalCDORevision.UNINITIALIZED);
         if (TRACER.isEnabled())
         {
-          TRACER.format("Additional value for index {0} ignored due to chunking. Setting uninitialized.", list.size());
+          TRACER.format("Added UNINITIALIZED for index {0} ", list.size());
         }
-
-        list.add(InternalCDORevision.UNINITIALIZED);
       }
+    }
+    catch (SQLException ex)
+    {
+      throw new DBException(ex);
+    }
+    finally
+    {
+      DBUtil.close(resultSet);
+      DBUtil.close(pstmt);
+    }
+
+    if (TRACER.isEnabled())
+    {
+      TRACER.format("Reading list values done for feature {0}.{1} of {2}v{3}", containingClass.getName(), feature
+          .getName(), revision.getID(), revision.getVersion());
+    }
+  }
+
+  /**
+   * Return the last (maximum) list index. (euals to size-1)
+   * 
+   * @param accessor
+   *          the accessor to use
+   * @param revision
+   *          the revision to which the feature list belongs
+   * @return the last index or <code>-1</code> if the list is empty.
+   */
+  private int getListLastIndex(IDBStoreAccessor accessor, InternalCDORevision revision)
+  {
+    PreparedStatement pstmt = null;
+    ResultSet resultSet = null;
+
+    try
+    {
+      pstmt = accessor.getConnection().prepareStatement(sqlGetListLastIndex);
+
+      setKeyFields(pstmt, revision);
 
       if (TRACER.isEnabled())
       {
-        TRACER.format("Reading list values done for feature {0}.{1} of {2}v{3}", containingClass.getName(), feature
-            .getName(), revision.getID(), revision.getVersion());
+        TRACER.trace(pstmt.toString());
+      }
+
+      resultSet = pstmt.executeQuery();
+
+      if (!resultSet.next())
+      {
+        if (TRACER.isEnabled())
+        {
+          TRACER.trace("No last index found -> list is empty. ");
+        }
+        return -1;
+      }
+      else
+      {
+        int result = resultSet.getInt(1);
+        if (TRACER.isEnabled())
+        {
+          TRACER.trace("Read list size = " + result);
+        }
+        return result;
       }
     }
     catch (SQLException ex)
@@ -242,7 +354,6 @@ public abstract class AbstractListTableMapping implements IListMapping
       DBUtil.close(resultSet);
       DBUtil.close(pstmt);
     }
-
   }
 
   public final void readChunks(IDBStoreChunkReader chunkReader, List<Chunk> chunks, String where)
@@ -338,10 +449,6 @@ public abstract class AbstractListTableMapping implements IListMapping
   {
     CDOList values = revision.getList(getFeature());
 
-    // if(values.contains(InternalCDORevision.UNINITIALIZED)) {
-    // readUninitializedValues(accessor, values);
-    // }
-
     int idx = 0;
     for (Object element : values)
     {
@@ -349,59 +456,6 @@ public abstract class AbstractListTableMapping implements IListMapping
     }
   }
 
-  // private void readUninitializedValues(IDBStoreAccessor accessor, CDORevision revision, MoveableList<Object> values)
-  // {
-  // CDOID id = revision.getID();
-  // int version = revision.getVersion();
-  //
-  // if (TRACER.isEnabled())
-  // {
-  // TRACER.format("Reading uninitialized list values for feature {0}.{1} of {2}v{3}", containingClass.getName(),
-  // feature.getName(),
-  // id, version);
-  // }
-  //
-  // PreparedStatement pstmt = null;
-  // ResultSet resultSet = null;
-  //
-  // try
-  // {
-  // String sql = sqlSelectChunksPrefix + sqlOrderByIndex;
-  //
-  // pstmt = accessor.getConnection().prepareStatement(sql);
-  //
-  // pstmt.setLong(1, CDOIDUtil.getLong(id));
-  // pstmt.setInt(2, version);
-  // if (TRACER.isEnabled())
-  // {
-  // TRACER.trace(pstmt.toString());
-  // }
-  //
-  // resultSet = pstmt.executeQuery();
-  //
-  // int index = 0;
-  //      
-  // while(resultSet.next()) {
-  // if(values.get(index) == InternalCDORevision.UNINITIALIZED) {
-  // Object value = typeMapping.readValue(resultSet, 1);
-  // if (TRACER.isEnabled())
-  // {
-  // TRACER.format("Read value for index {0} from result set: {1}", list.size(), value);
-  // }
-  // }
-  // }
-  // }
-  // catch (SQLException ex)
-  // {
-  // throw new DBException(ex);
-  // }
-  // finally
-  // {
-  // DBUtil.close(resultSet);
-  // DBUtil.close(pstmt);
-  // }
-  // }
-
   protected final void writeValue(IDBStoreAccessor accessor, CDORevision revision, int idx, Object value)
   {
     PreparedStatement stmt = null;
@@ -432,4 +486,32 @@ public abstract class AbstractListTableMapping implements IListMapping
       DBUtil.close(stmt);
     }
   }
+
+  /**
+   * Used by subclasses to indicate which fields should be in the table. I.e. just a pair of name and DBType ...
+   * 
+   * @author Stefan Winkler
+   */
+  protected static class FieldInfo
+  {
+    private String name;
+
+    private DBType dbType;
+
+    public FieldInfo(String name, DBType dbType)
+    {
+      this.name = name;
+      this.dbType = dbType;
+    }
+
+    public String getName()
+    {
+      return name;
+    }
+
+    public DBType getDbType()
+    {
+      return dbType;
+    }
+  }
 }
diff --git a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/horizontal/AuditListTableMapping.java b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/horizontal/AuditListTableMapping.java
index e2491414d7..23bad70f0c 100644
--- a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/horizontal/AuditListTableMapping.java
+++ b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/horizontal/AuditListTableMapping.java
@@ -1,5 +1,5 @@
 /**
- * Copyright (c) 2004 - 2009 Eike Stepper (Berlin, Germany) and others.
+ * Copyright (c) 2004 - 2009 Eike Stepper (Berlin, Germany) and others. 
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -7,7 +7,7 @@
  * 
  * Contributors:
  *    Eike Stepper - initial API and implementation
- *    Stefan Winkler - major refactoring
+ *    Stefan Winkler - 271444: [DB] Multiple refactorings https://bugs.eclipse.org/bugs/show_bug.cgi?id=271444  
  */
 package org.eclipse.emf.cdo.server.internal.db.mapping.horizontal;
 
@@ -27,14 +27,16 @@ import java.sql.PreparedStatement;
 import java.sql.SQLException;
 
 /**
+ * This is a list-table mapping for audit mode. It has ID and version columns and no delta support.
+ * 
  * @author Eike Stepper
  * @author Stefan Winkler
  * @since 2.0
  */
 public class AuditListTableMapping extends AbstractListTableMapping
 {
-  private static final FieldInfo[] KEY_FIELDS = { new FieldInfo(CDODBSchema.FEATURE_REVISION_ID, DBType.BIGINT),
-      new FieldInfo(CDODBSchema.FEATURE_REVISION_VERSION, DBType.INTEGER) };
+  private static final FieldInfo[] KEY_FIELDS = { new FieldInfo(CDODBSchema.LIST_REVISION_ID, DBType.BIGINT),
+      new FieldInfo(CDODBSchema.LIST_REVISION_VERSION, DBType.INTEGER) };
 
   public AuditListTableMapping(IMappingStrategy mappingStrategy, EClass eClass, EStructuralFeature feature)
   {
diff --git a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/horizontal/FieldInfo.java b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/horizontal/FieldInfo.java
deleted file mode 100644
index ef770ca06a..0000000000
--- a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/horizontal/FieldInfo.java
+++ /dev/null
@@ -1,42 +0,0 @@
-/**
- * Copyright (c) 2004 - 2009 Eike Stepper (Berlin, Germany) and others.
- * All rights reserved. This program and the accompanying materials
- * are made available under the terms of the Eclipse Public License v1.0
- * which accompanies this distribution, and is available at
- * http://www.eclipse.org/legal/epl-v10.html
- * 
- * Contributors:
- *    Eike Stepper - initial API and implementation
- *    Stefan Winkler - major refactoring
- */
-package org.eclipse.emf.cdo.server.internal.db.mapping.horizontal;
-
-import org.eclipse.net4j.db.DBType;
-
-/**
- * @author Eike Stepper
- * @author Stefan Winkler
- * @since 2.0
- */
-public class FieldInfo
-{
-  private String name;
-
-  private DBType dbType;
-
-  public FieldInfo(String name, DBType dbType)
-  {
-    this.name = name;
-    this.dbType = dbType;
-  }
-
-  public String getName()
-  {
-    return name;
-  }
-
-  public DBType getDbType()
-  {
-    return dbType;
-  }
-}
diff --git a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/horizontal/HorizontalAuditClassMapping.java b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/horizontal/HorizontalAuditClassMapping.java
index 64fa5a1c85..041856fc97 100644
--- a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/horizontal/HorizontalAuditClassMapping.java
+++ b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/horizontal/HorizontalAuditClassMapping.java
@@ -157,7 +157,7 @@ public class HorizontalAuditClassMapping extends AbstractHorizontalClassMapping
   }
 
   public boolean readRevisionByTime(IDBStoreAccessor accessor, InternalCDORevision revision, long timeStamp,
-      int referenceChunk)
+      int listChunk)
   {
     PreparedStatement pstmt = null;
     try
@@ -174,7 +174,7 @@ public class HorizontalAuditClassMapping extends AbstractHorizontalClassMapping
       // Read multival tables only if revision exists
       if (success)
       {
-        readLists(accessor, revision, referenceChunk);
+        readLists(accessor, revision, listChunk);
       }
 
       return success;
@@ -190,7 +190,7 @@ public class HorizontalAuditClassMapping extends AbstractHorizontalClassMapping
   }
 
   public boolean readRevisionByVersion(IDBStoreAccessor accessor, InternalCDORevision revision, int version,
-      int referenceChunk)
+      int listChunk)
   {
     PreparedStatement pstmt = null;
     try
@@ -206,7 +206,7 @@ public class HorizontalAuditClassMapping extends AbstractHorizontalClassMapping
       // Read multival tables only if revision exists
       if (success)
       {
-        readLists(accessor, revision, referenceChunk);
+        readLists(accessor, revision, listChunk);
       }
 
       return success;
@@ -318,7 +318,7 @@ public class HorizontalAuditClassMapping extends AbstractHorizontalClassMapping
     }
   }
 
-  public boolean readRevision(IDBStoreAccessor accessor, InternalCDORevision revision, int referenceChunk)
+  public boolean readRevision(IDBStoreAccessor accessor, InternalCDORevision revision, int listChunk)
   {
     PreparedStatement pstmt = null;
     try
@@ -333,7 +333,7 @@ public class HorizontalAuditClassMapping extends AbstractHorizontalClassMapping
       // Read multival tables only if revision exists
       if (success)
       {
-        readLists(accessor, revision, referenceChunk);
+        readLists(accessor, revision, listChunk);
       }
 
       return success;
diff --git a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/horizontal/HorizontalNonAuditClassMapping.java b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/horizontal/HorizontalNonAuditClassMapping.java
index eaaf72e34a..16880550fc 100644
--- a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/horizontal/HorizontalNonAuditClassMapping.java
+++ b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/horizontal/HorizontalNonAuditClassMapping.java
@@ -293,7 +293,7 @@ public class HorizontalNonAuditClassMapping extends AbstractHorizontalClassMappi
     }
   }
 
-  public boolean readRevision(IDBStoreAccessor accessor, InternalCDORevision revision, int referenceChunk)
+  public boolean readRevision(IDBStoreAccessor accessor, InternalCDORevision revision, int listChunk)
   {
     PreparedStatement pstmt = null;
     try
@@ -308,7 +308,7 @@ public class HorizontalNonAuditClassMapping extends AbstractHorizontalClassMappi
       // Read multival tables only if revision exists
       if (success)
       {
-        readLists(accessor, revision, referenceChunk);
+        readLists(accessor, revision, listChunk);
       }
 
       return success;
diff --git a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/horizontal/NonAuditListTableMapping.java b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/horizontal/NonAuditListTableMapping.java
index 53f23a28ed..0f4e3fe60d 100644
--- a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/horizontal/NonAuditListTableMapping.java
+++ b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/horizontal/NonAuditListTableMapping.java
@@ -1,5 +1,5 @@
 /**
- * Copyright (c) 2004 - 2009 Eike Stepper (Berlin, Germany) and others.
+ * Copyright (c) 2004 - 2009 Eike Stepper (Berlin, Germany) and others. 
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -7,7 +7,7 @@
  * 
  * Contributors:
  *    Eike Stepper - initial API and implementation
- *    Stefan Winkler - major refactoring
+ *    Stefan Winkler - 271444: [DB] Multiple refactorings https://bugs.eclipse.org/bugs/show_bug.cgi?id=271444  
  */
 package org.eclipse.emf.cdo.server.internal.db.mapping.horizontal;
 
@@ -32,6 +32,8 @@ import java.sql.PreparedStatement;
 import java.sql.SQLException;
 
 /**
+ * This is a list-to-table mapping optimized for non-audit-mode. It doesn't care about version and has delta support.
+ * 
  * @author Eike Stepper
  * @author Stefan Winkler
  * @since 2.0
@@ -39,7 +41,7 @@ import java.sql.SQLException;
 public class NonAuditListTableMapping extends AbstractListTableMapping implements IListMapping,
     IListMappingDeltaSupport
 {
-  private static final FieldInfo[] KEY_FIELDS = { new FieldInfo(CDODBSchema.FEATURE_REVISION_ID, DBType.BIGINT) };
+  private static final FieldInfo[] KEY_FIELDS = { new FieldInfo(CDODBSchema.LIST_REVISION_ID, DBType.BIGINT) };
 
   private static final int TEMP_INDEX = -1;
 
@@ -78,13 +80,13 @@ public class NonAuditListTableMapping extends AbstractListTableMapping implement
     builder.append("DELETE FROM ");
     builder.append(getTable().getName());
     builder.append(" WHERE ");
-    builder.append(CDODBSchema.FEATURE_REVISION_ID);
+    builder.append(CDODBSchema.LIST_REVISION_ID);
     builder.append(" = ? ");
 
     sqlClear = builder.toString();
 
     builder.append(" AND ");
-    builder.append(CDODBSchema.FEATURE_IDX);
+    builder.append(CDODBSchema.LIST_IDX);
     builder.append(" = ? ");
 
     sqlDeleteItem = builder.toString();
@@ -94,12 +96,12 @@ public class NonAuditListTableMapping extends AbstractListTableMapping implement
     builder.append("UPDATE ");
     builder.append(getTable().getName());
     builder.append(" SET ");
-    builder.append(CDODBSchema.FEATURE_TARGET);
+    builder.append(CDODBSchema.LIST_VALUE);
     builder.append(" = ? ");
     builder.append(" WHERE ");
-    builder.append(CDODBSchema.FEATURE_REVISION_ID);
+    builder.append(CDODBSchema.LIST_REVISION_ID);
     builder.append(" = ? AND ");
-    builder.append(CDODBSchema.FEATURE_IDX);
+    builder.append(CDODBSchema.LIST_IDX);
     builder.append(" = ? ");
     sqlUpdateValue = builder.toString();
 
@@ -115,12 +117,12 @@ public class NonAuditListTableMapping extends AbstractListTableMapping implement
     builder.append("UPDATE ");
     builder.append(getTable().getName());
     builder.append(" SET ");
-    builder.append(CDODBSchema.FEATURE_IDX);
+    builder.append(CDODBSchema.LIST_IDX);
     builder.append(" = ? ");
     builder.append(" WHERE ");
-    builder.append(CDODBSchema.FEATURE_REVISION_ID);
+    builder.append(CDODBSchema.LIST_REVISION_ID);
     builder.append(" = ? AND ");
-    builder.append(CDODBSchema.FEATURE_IDX);
+    builder.append(CDODBSchema.LIST_IDX);
     builder.append(" = ? ");
     sqlUpdateIndex = builder.toString();
 
@@ -129,18 +131,18 @@ public class NonAuditListTableMapping extends AbstractListTableMapping implement
     builder.append("UPDATE ");
     builder.append(getTable().getName());
     builder.append(" SET ");
-    builder.append(CDODBSchema.FEATURE_IDX);
+    builder.append(CDODBSchema.LIST_IDX);
     builder.append(" = ");
-    builder.append(CDODBSchema.FEATURE_IDX);
+    builder.append(CDODBSchema.LIST_IDX);
     builder.append("-1 WHERE ");
-    builder.append(CDODBSchema.FEATURE_REVISION_ID);
+    builder.append(CDODBSchema.LIST_REVISION_ID);
     builder.append("= ? AND ");
-    builder.append(CDODBSchema.FEATURE_IDX);
+    builder.append(CDODBSchema.LIST_IDX);
     builder.append(" > ? ");
     sqlMoveDown = builder.toString();
 
     builder.append(" AND ");
-    builder.append(CDODBSchema.FEATURE_IDX);
+    builder.append(CDODBSchema.LIST_IDX);
     builder.append(" <= ?");
     sqlMoveDownWithLimit = builder.toString();
 
@@ -149,18 +151,18 @@ public class NonAuditListTableMapping extends AbstractListTableMapping implement
     builder.append("UPDATE ");
     builder.append(getTable().getName());
     builder.append(" SET ");
-    builder.append(CDODBSchema.FEATURE_IDX);
+    builder.append(CDODBSchema.LIST_IDX);
     builder.append(" = ");
-    builder.append(CDODBSchema.FEATURE_IDX);
+    builder.append(CDODBSchema.LIST_IDX);
     builder.append("+1 WHERE ");
-    builder.append(CDODBSchema.FEATURE_REVISION_ID);
+    builder.append(CDODBSchema.LIST_REVISION_ID);
     builder.append("= ? AND ");
-    builder.append(CDODBSchema.FEATURE_IDX);
+    builder.append(CDODBSchema.LIST_IDX);
     builder.append(" >= ? ");
     sqlMoveUp = builder.toString();
 
     builder.append(" AND ");
-    builder.append(CDODBSchema.FEATURE_IDX);
+    builder.append(CDODBSchema.LIST_IDX);
     builder.append(" < ?");
     sqlMoveUpWithLimit = builder.toString();