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| <title>Chapter 7. Mapping</title><link rel="stylesheet" href="css/docbook.css" type="text/css"><base href="display"><meta name="generator" content="DocBook XSL Stylesheets V1.72.0"><link rel="start" href="manual.html" title="Apache OpenJPA 2.0 User's Guide"><link rel="up" href="ref_guide.html" title="Part 3. Reference Guide"><link rel="prev" href="ref_guide_meta_ext.html" title="4. Metadata Extensions"><link rel="next" href="ref_guide_pc_reverse.html" title="2. Reverse Mapping"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">Chapter 7. |
| Mapping |
| </th></tr><tr><td width="20%" align="left"><a accesskey="p" href="ref_guide_meta_ext.html">Prev</a> </td><th width="60%" align="center">Part 3. Reference Guide</th><td width="20%" align="right"> <a accesskey="n" href="ref_guide_pc_reverse.html">Next</a></td></tr></table><hr></div><div class="chapter" lang="en" id="ref_guide_mapping"><div class="titlepage"><div><div><h2 class="title"><a name="ref_guide_mapping"></a>Chapter 7. |
| Mapping |
| </h2></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="section"><a href="ref_guide_mapping.html#ref_guide_mapping_mappingtool">1. |
| Forward Mapping |
| </a></span></dt><dd><dl><dt><span class="section"><a href="ref_guide_mapping.html#ref_guide_mapping_mappingtool_examples">1.1. |
| Using the Mapping Tool |
| </a></span></dt><dt><span class="section"><a href="ref_guide_mapping.html#ref_guide_ddl_examples">1.2. |
| Generating DDL SQL |
| </a></span></dt><dt><span class="section"><a href="ref_guide_mapping.html#ref_guide_mapping_synch">1.3. |
| Runtime Forward Mapping |
| </a></span></dt></dl></dd><dt><span class="section"><a href="ref_guide_pc_reverse.html">2. |
| Reverse Mapping |
| </a></span></dt><dd><dl><dt><span class="section"><a href="ref_guide_pc_reverse.html#ref_guide_pc_reverse_custom">2.1. |
| Customizing Reverse Mapping |
| </a></span></dt></dl></dd><dt><span class="section"><a href="ref_guide_mapping_middle.html">3. |
| Meet-in-the-Middle Mapping |
| </a></span></dt><dt><span class="section"><a href="ref_guide_mapping_defaults.html">4. |
| Mapping Defaults |
| </a></span></dt><dt><span class="section"><a href="ref_guide_mapping_factory.html">5. |
| Mapping Factory |
| </a></span></dt><dt><span class="section"><a href="ref_guide_mapping_notes_nonstdjoins.html">6. |
| Non-Standard Joins |
| </a></span></dt><dt><span class="section"><a href="ref_guide_mapping_jpa.html">7. |
| Additional JPA Mappings |
| </a></span></dt><dd><dl><dt><span class="section"><a href="ref_guide_mapping_jpa.html#ref_guide_mapping_jpa_datastoreid">7.1. |
| Datastore Identity Mapping |
| </a></span></dt><dt><span class="section"><a href="ref_guide_mapping_jpa.html#ref_guide_mapping_jpa_version">7.2. |
| Surrogate Version Mapping |
| </a></span></dt><dt><span class="section"><a href="ref_guide_mapping_jpa.html#ref_guide_mapping_jpa_columns">7.3. |
| Multi-Column Mappings |
| </a></span></dt><dt><span class="section"><a href="ref_guide_mapping_jpa.html#ref_guide_mapping_jpa_fieldjoin">7.4. |
| Join Column Attribute Targets |
| </a></span></dt><dt><span class="section"><a href="ref_guide_mapping_jpa.html#ref_guide_mapping_jpa_embed">7.5. |
| Embedded Mapping |
| </a></span></dt><dt><span class="section"><a href="ref_guide_mapping_jpa.html#ref_guide_mapping_jpa_coll">7.6. |
| Collections |
| </a></span></dt><dd><dl><dt><span class="section"><a href="ref_guide_mapping_jpa.html#ref_guide_mapping_jpa_coll_table">7.6.1. |
| Container Table |
| </a></span></dt><dt><span class="section"><a href="ref_guide_mapping_jpa.html#ref_guide_mapping_jpa_coll_joincols">7.6.2. |
| Element Join Columns |
| </a></span></dt><dt><span class="section"><a href="ref_guide_mapping_jpa.html#ref_guide_mapping_jpa_coll_order">7.6.3. |
| Order Column |
| </a></span></dt></dl></dd><dt><span class="section"><a href="ref_guide_mapping_jpa.html#ref_guide_mapping_jpa_onemany">7.7. |
| One-Sided One-Many Mapping |
| </a></span></dt><dt><span class="section"><a href="ref_guide_mapping_jpa.html#ref_guide_mapping_jpa_map">7.8. |
| Maps |
| </a></span></dt><dd><dl><dt><span class="section"><a href="ref_guide_mapping_jpa.html#ref_guide_mapping_jpa_map_keycols">7.8.1. Key Columns</a></span></dt><dt><span class="section"><a href="ref_guide_mapping_jpa.html#ref_guide_mapping_jpa_map_keyjoincols">7.8.2. Key Join Columns</a></span></dt><dt><span class="section"><a href="ref_guide_mapping_jpa.html#ref_guide_mapping_jpa_map_embedkey">7.8.3. Key Embedded Mapping</a></span></dt><dt><span class="section"><a href="ref_guide_mapping_jpa.html#ref_guide_mapping_jpa_map_ex">7.8.4. Examples</a></span></dt></dl></dd><dt><span class="section"><a href="ref_guide_mapping_jpa.html#ref_guide_mapping_jpa_constraints">7.9. |
| Indexes and Constraints |
| </a></span></dt><dd><dl><dt><span class="section"><a href="ref_guide_mapping_jpa.html#ref_guide_mapping_jpa_index">7.9.1. |
| Indexes |
| </a></span></dt><dt><span class="section"><a href="ref_guide_mapping_jpa.html#ref_guide_mapping_jpa_fk">7.9.2. |
| Foreign Keys |
| </a></span></dt><dt><span class="section"><a href="ref_guide_mapping_jpa.html#ref_guide_mapping_jpa_unique">7.9.3. |
| Unique Constraints |
| </a></span></dt></dl></dd><dt><span class="section"><a href="ref_guide_mapping_jpa.html#ref_guide_xmlmapping">7.10. |
| XML Column Mapping |
| </a></span></dt><dt><span class="section"><a href="ref_guide_mapping_jpa.html#ref_guide_streamsupport">7.11. |
| LOB Streaming |
| </a></span></dt></dl></dd><dt><span class="section"><a href="ref_guide_mapping_limits.html">8. |
| Mapping Limitations |
| </a></span></dt><dd><dl><dt><span class="section"><a href="ref_guide_mapping_limits.html#ref_guide_mapping_limits_tpc">8.1. |
| Table Per Class |
| </a></span></dt></dl></dd><dt><span class="section"><a href="ref_guide_mapping_ext.html">9. |
| Mapping Extensions |
| </a></span></dt><dd><dl><dt><span class="section"><a href="ref_guide_mapping_ext.html#ref_guide_mapping_ext_cls">9.1. |
| Class Extensions |
| </a></span></dt><dd><dl><dt><span class="section"><a href="ref_guide_mapping_ext.html#subclass-fetch-mode">9.1.1. |
| Subclass Fetch Mode |
| </a></span></dt><dt><span class="section"><a href="ref_guide_mapping_ext.html#class-strategy">9.1.2. |
| Strategy |
| </a></span></dt><dt><span class="section"><a href="ref_guide_mapping_ext.html#discriminator-strategy">9.1.3. |
| Discriminator Strategy |
| </a></span></dt><dt><span class="section"><a href="ref_guide_mapping_ext.html#version-strategy">9.1.4. |
| Version Strategy |
| </a></span></dt></dl></dd><dt><span class="section"><a href="ref_guide_mapping_ext.html#ref_guide_mapping_ext_field">9.2. |
| Field Extensions |
| </a></span></dt><dd><dl><dt><span class="section"><a href="ref_guide_mapping_ext.html#eager-fetch-mode">9.2.1. |
| Eager Fetch Mode |
| </a></span></dt><dt><span class="section"><a href="ref_guide_mapping_ext.html#nonpolymorphic">9.2.2. |
| Nonpolymorphic |
| </a></span></dt><dt><span class="section"><a href="ref_guide_mapping_ext.html#class-criteria">9.2.3. |
| Class Criteria |
| </a></span></dt><dt><span class="section"><a href="ref_guide_mapping_ext.html#strategy">9.2.4. |
| Strategy |
| </a></span></dt></dl></dd></dl></dd><dt><span class="section"><a href="ref_guide_mapping_custom.html">10. |
| Custom Mappings |
| </a></span></dt><dd><dl><dt><span class="section"><a href="ref_guide_mapping_custom.html#ref_guide_mapping_custom_class">10.1. |
| Custom Class Mapping |
| </a></span></dt><dt><span class="section"><a href="ref_guide_mapping_custom.html#ref_guide_mapping_custom_versdiscrim">10.2. |
| Custom Discriminator and Version Strategies |
| </a></span></dt><dt><span class="section"><a href="ref_guide_mapping_custom.html#ref_guide_mapping_custom_field">10.3. |
| Custom Field Mapping |
| </a></span></dt><dd><dl><dt><span class="section"><a href="ref_guide_mapping_custom.html#ref_guide_mapping_custom_vhandler">10.3.1. |
| Value Handlers |
| </a></span></dt><dt><span class="section"><a href="ref_guide_mapping_custom.html#ref_guide_mapping_custom_fieldstrat">10.3.2. |
| Field Strategies |
| </a></span></dt><dt><span class="section"><a href="ref_guide_mapping_custom.html#ref_guide_mapping_custom_field_conf">10.3.3. |
| Configuration |
| </a></span></dt></dl></dd></dl></dd><dt><span class="section"><a href="ref_guide_orphan.html">11. |
| Orphaned Keys |
| </a></span></dt></dl></div><a class="indexterm" name="d0e27837"></a><p> |
| The JPA Overview's <a href="jpa_overview_mapping.html" title="Chapter 13. Mapping Metadata">Chapter 13, <i xmlns:xlink="http://www.w3.org/1999/xlink"> |
| Mapping Metadata |
| </i></a> explains |
| object-relational mapping under JPA. This chapter reviews the mapping utilities |
| OpenJPA provides and examines OpenJPA features that go beyond the JPA |
| specification. |
| </p><div class="section" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="ref_guide_mapping_mappingtool"></a>1. |
| Forward Mapping |
| </h2></div></div></div><div class="toc"><dl><dt><span class="section"><a href="ref_guide_mapping.html#ref_guide_mapping_mappingtool_examples">1.1. |
| Using the Mapping Tool |
| </a></span></dt><dt><span class="section"><a href="ref_guide_mapping.html#ref_guide_ddl_examples">1.2. |
| Generating DDL SQL |
| </a></span></dt><dt><span class="section"><a href="ref_guide_mapping.html#ref_guide_mapping_synch">1.3. |
| Runtime Forward Mapping |
| </a></span></dt></dl></div><a class="indexterm" name="d0e27847"></a><a class="indexterm" name="d0e27850"></a><a class="indexterm" name="d0e27855"></a><p> |
| <span class="emphasis"><em>Forward mapping</em></span> is the process of creating mappings and |
| their corresponding database schema from your object model. OpenJPA supports |
| forward mapping through the <span class="emphasis"><em>mapping tool</em></span>. The next section |
| presents several common mapping tool use cases. You can invoke the tool through |
| its Java class, |
| <a xmlns:xlink="http://www.w3.org/1999/xlink" href="../javadoc/org/apache/openjpa/jdbc/meta/MappingTool" target="_top"><code class="classname"> |
| org.apache.openjpa.jdbc.meta.MappingTool</code></a>. |
| </p><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3><p> |
| <a href="ref_guide_integration.html#ref_guide_integration_mappingtool" title="1.4. Mapping Tool Ant Task">Section 1.4, “ |
| Mapping Tool Ant Task |
| ”</a> describes the mapping |
| tool Ant task. |
| </p></div><div class="example"><a name="ref_guide_mapping_mappingtool_typical"></a><p class="title"><b>Example 7.1. |
| Using the Mapping Tool |
| </b></p><div class="example-contents"><pre class="programlisting"> |
| java org.apache.openjpa.jdbc.meta.MappingTool Magazine.java |
| </pre></div></div><br class="example-break"><p> |
| In addition to the universal flags of the |
| <a href="ref_guide_conf_devtools.html" title="3. Command Line Configuration">configuration framework</a>, the |
| mapping tool accepts the following command line arguments: |
| </p><div class="itemizedlist"><ul type="disc"><li><p> |
| <code class="literal">-schemaAction/-sa <add | refresh | drop | build | retain | reflect | createDB | dropDB | import | export | none> |
| </code>: The action to take on the schema. These options correspond to the |
| same-named actions on the schema tool described in |
| <a href="ref_guide_schema_schematool.html" title="13. Schema Tool">Section 13, “ |
| Schema Tool |
| ”</a>. Actions can be composed in a |
| comma-separated list. Unless you are running the mapping tool on all of |
| your persistent types at once or dropping a mapping, we strongly |
| recommend you use the default <code class="literal">add</code> action or the |
| <code class="literal">build</code> action. Otherwise you may end up inadvertently |
| dropping schema components that are used by classes you are not |
| currently running the tool over. |
| </p></li><li><p> |
| <code class="literal">-schemaFile/-sf <stdout | output file></code>: Use this |
| option to write the planned schema to an XML document rather than modify the |
| database. The document can then be manipulated and committed to the database |
| with the <a href="ref_guide_schema_schematool.html" title="13. Schema Tool"> schema tool</a>. |
| </p></li><li><p> |
| <code class="literal">-sqlFile/-sql <stdout | output file></code>: Use this option |
| to write the planned schema modifications to a SQL script rather than modify the |
| database. Combine this with a <code class="literal">schemaAction</code> of <code class="literal">build |
| </code> to generate a script that recreates the schema for the current |
| mappings, even if the schema already exists. |
| </p></li><li><p> |
| <code class="literal">-dropTables/-dt <true/t | false/f></code>: Corresponds to the |
| same-named option on the schema tool. |
| </p></li><li><p> |
| <code class="literal">-dropSequences/-dsq <true/t | false/f></code>: Corresponds to |
| the same-named option on the schema tool. |
| </p></li><li><p> |
| <code class="literal">-openjpaTables/-ot <true/t | false/f></code>: Corresponds to |
| the same-named option on the schema tool. |
| </p></li><li><p> |
| <code class="literal">-ignoreErrors/-i <true/t | false/f></code>: Corresponds to |
| the same-named option on the schema tool. |
| </p></li><li><p> |
| <code class="literal">-schemas/-s <schema and table names></code>: Corresponds to |
| the same-named option on the schema tool. This option is ignored if <code class="literal"> |
| readSchema</code> is not set to <code class="literal">true</code>. |
| </p></li><li><p> |
| <code class="literal">-readSchema/-rs <true/t | false/f></code>: Set this option to |
| <code class="literal">true</code> to read the entire existing schema when the tool runs. |
| Reading the existing schema ensures that OpenJPA does not generate any mappings |
| that use table, index, primary key, or foreign key names that conflict with |
| existing names. Depending on the JDBC driver, though, it can be a slow process |
| for large schemas. |
| </p></li><li><p> |
| <code class="literal">-primaryKeys/-pk <true/t | false/f></code>: Whether to read |
| and manipulate primary key information of existing tables. Defaults to false. |
| </p></li><li><p> |
| <code class="literal">-foreignKeys/-fk <true/t | false/f></code>: Whether to read |
| and manipulate foreign key information of existing tables. Defaults to false. |
| This means that to add any new foreign keys to a class that has already been |
| mapped, you must explicitly set this flag to true. |
| </p></li><li><p> |
| <code class="literal">-indexes/-ix <true/t | false/f></code>: Whether to read and |
| manipulate index information of existing tables. Defaults to false. This means |
| that to add any new indexes to a class that has already been mapped once, you |
| must explicitly set this flag to true. |
| </p></li><li><p> |
| <code class="literal">-sequences/-sq <true/t | false/f></code>: Whether to |
| manipulate sequences. Defaults to true. |
| </p></li><li><p> |
| <code class="literal">-meta/-m <true/t | false/f></code>: Whether the given action |
| applies to metadata rather than or in addition to mappings. |
| </p></li></ul></div><p> |
| The mapping tool also uses an <code class="literal">-action/-a</code> argument to specify |
| the action to take on each class. The available actions are: |
| </p><div class="itemizedlist"><ul type="disc"><li><p> |
| <code class="literal">buildSchema</code>: This is the default action. It |
| makes the database schema match your existing mappings. If your provided |
| mappings conflict with your class definitions, OpenJPA will fail with an |
| informative exception. |
| </p></li><li><p> |
| <code class="literal">validate</code>: Ensure that the mappings for the given classes are |
| valid and that they match the schema. No mappings or tables will be changed. An |
| exception is thrown if any mappings are invalid. |
| </p></li></ul></div><p> |
| Each additional argument to the tool should be one of: |
| </p><div class="itemizedlist"><ul type="disc"><li><p> |
| The full name of a persistent class. |
| </p></li><li><p> |
| The .java file for a persistent class. |
| </p></li><li><p> |
| The <code class="filename">.class</code> file of a persistent class. |
| </p></li></ul></div><p> |
| If you do not supply any arguments to the mapping tool, it will run on the |
| classes in your persistent classes list (see |
| <a href="ref_guide_pc.html#ref_guide_pc_pcclasses" title="1. Persistent Class List">Section 1, “ |
| Persistent Class List |
| ”</a>). |
| </p><p> |
| The mappings generated by the mapping tool are stored by the system <span class="emphasis"><em> |
| mapping factory</em></span>. <a href="ref_guide_mapping_factory.html" title="5. Mapping Factory">Section 5, “ |
| Mapping Factory |
| ”</a> |
| discusses your mapping factory options. |
| </p><div class="section" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="ref_guide_mapping_mappingtool_examples"></a>1.1. |
| Using the Mapping Tool |
| </h3></div></div></div><a class="indexterm" name="d0e28047"></a><p> |
| The JPA specification defines a comprehensive set of defaults for missing |
| mapping information. Thus, forward mapping in JPA is virtually automatic. After |
| using the mapping annotations covered in <a href="jpa_overview_mapping.html" title="Chapter 13. Mapping Metadata">Chapter 13, <i xmlns:xlink="http://www.w3.org/1999/xlink"> |
| Mapping Metadata |
| </i></a> |
| of the JPA Overview to override any unsatisfactory defaults, run the |
| mapping tool on your persistent classes. The default <code class="literal">buildSchema |
| </code> mapping tool action manipulates the database schema to |
| match your mappings. It fails if any of your mappings don't match your object |
| model. |
| </p><div class="example"><a name="ref_guide_mapping_mappingtool_buildschema"></a><p class="title"><b>Example 7.2. |
| Creating the Relational Schema from Mappings |
| </b></p><div class="example-contents"><pre class="programlisting"> |
| java org.apache.openjpa.jdbc.meta.MappingTool Magazine.java |
| </pre></div></div><br class="example-break"><p> |
| To drop the schema for a persistent class, set the mapping tool's <code class="literal"> |
| schemaAction</code> to <code class="literal">drop</code>. |
| </p><div class="example"><a name="ref_guide_mapping_mappingtool_cleanup_tables"></a><p class="title"><b>Example 7.3. |
| Refreshing entire schema and cleaning out tables |
| </b></p><div class="example-contents"><a class="indexterm" name="d0e28075"></a><pre class="programlisting"> |
| java org.apache.openjpa.jdbc.meta.MappingTool -schemaAction add,deleteTableContents |
| </pre></div></div><br class="example-break"><div class="example"><a name="ref_guide_mapping_mappingtool_dropschema"></a><p class="title"><b>Example 7.4. |
| Dropping Mappings and Association Schema |
| </b></p><div class="example-contents"><pre class="programlisting"> |
| java org.apache.openjpa.jdbc.meta.MappingTool -schemaAction drop Magazine.java |
| </pre></div></div><br class="example-break"></div><div class="section" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="ref_guide_ddl_examples"></a>1.2. |
| Generating DDL SQL |
| </h3></div></div></div><a class="indexterm" name="d0e28090"></a><a class="indexterm" name="d0e28095"></a><p> |
| The examples below show how to use the mapping tool to generate DDL SQL scripts, |
| rather than modifying the database directly. |
| </p><div class="example"><a name="ref_guid_mapping_ddl_full_ddl"></a><p class="title"><b>Example 7.5. |
| Create DDL for Current Mappings |
| </b></p><div class="example-contents"><p> |
| This example uses your existing mappings to determine the needed schema, then |
| writes the SQL to create that schema to <code class="filename">create.sql</code>. |
| </p><pre class="programlisting"> |
| java org.apache.openjpa.jdbc.meta.MappingTool -schemaAction build -sql create.sql Magazine.java |
| </pre></div></div><br class="example-break"><div class="example"><a name="ref_guid_mapping_ddl_part_ddl"></a><p class="title"><b>Example 7.6. |
| Create DDL to Update Database for Current Mappings |
| </b></p><div class="example-contents"><p> |
| This example uses your existing mappings to determine the needed schema. It then |
| writes the SQL to add any missing tables and columns to the current schema to |
| <code class="filename">update.sql</code>. |
| </p><pre class="programlisting"> |
| java org.apache.openjpa.jdbc.meta.MappingTool -sql update.sql Magazine.java |
| </pre></div></div><br class="example-break"></div><div class="section" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="ref_guide_mapping_synch"></a>1.3. |
| Runtime Forward Mapping |
| </h3></div></div></div><a class="indexterm" name="d0e28125"></a><a class="indexterm" name="d0e28130"></a><p> |
| You can configure OpenJPA to automatically run the mapping tool at runtime |
| through the <a href="ref_guide_conf_jdbc.html#openjpa.jdbc.SynchronizeMappings" title="6.17. openjpa.jdbc.SynchronizeMappings"><code class="literal"> |
| openjpa.jdbc.SynchronizeMappings</code></a> configuration property. Using |
| this property saves you the trouble of running the mapping tool manually, and is |
| meant for use during rapid test/debug cycles. |
| </p><p> |
| In order to enable automatic runtime mapping, you must first list all your |
| persistent classes as described in <a href="ref_guide_pc.html#ref_guide_pc_pcclasses" title="1. Persistent Class List">Section 1, “ |
| Persistent Class List |
| ”</a>. |
| </p><p> |
| OpenJPA will run the mapping tool on these classes when your application obtains |
| its first <code class="classname">EntityManager</code>. |
| </p><p> |
| The <code class="literal">openjpa.jdbc.SynchronizeMappings</code> property is a plugin |
| string (see <a href="ref_guide_conf_plugins.html" title="4. Plugin Configuration">Section 4, “ |
| Plugin Configuration |
| ”</a>) where the class |
| name is the mapping tool action to invoke, and the properties are the |
| <code class="classname">MappingTool</code> class' JavaBean properties. These properties |
| correspond go the long versions of the tool's command line flags. |
| </p><div class="example"><a name="ref_guide_mapping_synchex"></a><p class="title"><b>Example 7.7. |
| Configuring Runtime Forward Mapping |
| </b></p><div class="example-contents"><pre class="programlisting"> |
| <property name="openjpa.jdbc.SynchronizeMappings" value="buildSchema(ForeignKeys=true)"/> |
| </pre><p> |
| The setting above corresponds to running the following command: |
| </p><pre class="programlisting"> |
| java org.apache.openjpa.jdbc.meta.MappingTool -action buildSchema -foreignKeys true |
| </pre></div></div><br class="example-break"></div></div></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="ref_guide_meta_ext.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="ref_guide.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="ref_guide_pc_reverse.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">4. |
| Metadata Extensions |
| </td><td width="20%" align="center"><a accesskey="h" href="manual.html">Home</a></td><td width="40%" align="right" valign="top"> 2. |
| Reverse Mapping |
| </td></tr></table></div></body></html> |
