Java Persistence API (JPA) Extensions Reference for EclipseLink, Release 2.6
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6 eclipselink-orm.xml Schema Reference

This chapter describes how you can use EclipseLink's native metadata XML file, eclipselink-orm.xml, to override mappings defined in the JPA configuration file (orm.xml) and to provide extended ORM features.


NoteNote:

Using the eclipselink-orm.xml mapping file enables many EclipseLink advanced features, but it may prevent the persistence unit from being portable to other JPA implementations.


The eclipselink-orm.xml file defines object-relational mapping metadata for EclipseLink. It has the same basic structure as the orm.xml file, which makes it more intuitive, requires minimum configuration, and makes it easy to override.

For more information, see:

The schema for EclipseLink is eclipselink_orm_X_X.xsd where X_X is the current EclipseLink version number (such as 2_4 for 2.4). All EclipseLink schemas are available from http://wiki.eclipse.org/EclipseLink/XSDs.

This chapter includes the following sections:

Overriding and Merging

To override the orm.xml file's mapping, you must define the META-INF/eclipselink-orm.xml file in the project. When both orm.xml and eclipselink-orm.xml are specified, the contents of eclipselink-orm.xml will override orm.xml and any other JPA mapping file specified in the persistence unit. If there are overlapping specifications in multiple ORM files, the files are merged if they are no conflicting entities.


NoteNote:

The order of files defined in persistence.xml does not define the order of their processing. The files are processed, merged, and overridden as determined by the rules.


See the following sections for more information:

Rules for Overriding and Merging

EclipseLink provides specific overriding and merging rules for the following elements defined in the orm.xml file:

Persistence Unit Metadata

In eclipselink-orm.xml, a persistence-unit-metadata element merges or overrides the values of existing persistence-unit-metadata specification as defined in Table 6-1.

Table 6-1 Overriding and Merging Persistence Unit Metadata

entity-mappings/ persistence-unit-metadata Rule Description

xml-mapping-metadata- complete

Full override

If specified, the complete set of mapping metadata for the persistence unit is contained in the XML mapping files for the persistence unit.

persistence-unit-defaults/ schema

Full override

If a schema setting exists, then the eclipselink-orm.xml schema setting overrides the existing setting or creates a new schema setting.

persistence-unit-defaults/ catalog

Full override

If a catalog setting exists, then the eclipselink-orm.xml catalog setting overrides the existing setting or creates a new catalog setting

persistence-unit-defaults/ access

Full override

If an access setting exists, then the eclipselink-orm.xml access setting overrides the existing setting, or creates a new access setting.

entity-mappings/persistence-unit-metadata/persistence-unit-defaults/cascade- persist

Full override

If a cascade-persist setting exists, then the eclipselink-orm.xml cascade-persist setting overrides the existing setting or creates a new cascade-persist setting.

entity-mappings/persistence-unit-metadata/persistence-unit-defaults/entity- listeners

Merge

If an entity-listeners exists, then the eclipselink-orm.xml entity-listeners will be merged with the list of all entity-listeners from the persistence unit


Entity Mappings

Entities, embeddables and mapped superclasses are defined within the entity-mappings section. The eclipselink-orm.xml entities, embeddables and mapped superclasses are added to the persistence unit as defined in Table 6-2.

Table 6-2 Overriding and Merging Entity Mappings

entity-mappings/ Rule Description

package

None

The package element specifies the package of the classes listed within the subelements and attributes of the same mapping file only. It is only applicable to those entities that are fully defined within the eclipselink-orm.xml file, else its usage remains local and is same as described in the JPA specification.

catalog

None

The catalog element applies only to the subelements and attributes listed within the eclipselink-orm.xml file that are not an extension to another mapping file. Otherwise, the use of the catalog element within the eclipselink-orm.xml file remains local and is same as described in the JPA specification.

schema

None

The schema element applies only to the subelements and attributes listed within the eclipselink-orm.xml file that are not an extension to another mapping file. Otherwise, the use of the schema element within the eclipselink-orm.xml file remains local and is same as described in the JPA specification.

access

None

The access element applies only to the subelements and attributes listed within the eclipselink-orm.xml file that are not an extension to another mapping file. Otherwise, the use of the access element within the eclipselink-orm.xml file remains local and is same as described in the JPA specification.

sequence-generator

Full override

A sequence-generator is unique by name. The sequence-generator defined in the eclipselink-orm.xml will override a sequence-generator of the same name defined in another mapping file. Outside of the overriding case, an exception is thrown if two or more sequence-generators with the same name are defined in one or across multiple mapping files.

table-generator

Full override

A table-generator is unique by name. The table-generator defined in the eclipselink-orm.xml will override a table-generator of the same name defined in another mapping file. Outside of the overriding case, an exception is thrown if two or more table-generators with the same name are defined in one or across multiple mapping files.

named-query

Full override

A named-query is unique by name. The named-query defined in the eclipselink-orm.xml will override a named-query of the same name defined in other mapping files. Outside of the overriding case, an exception is thrown if two or more named-querys with the same name are defined in one or across multiple mapping file.

named-native-query

Full override

A named-native-query is unique by name. The named-native-query defined in the eclipselink-orm.xml will override a named-native-query of the same name defined in other mapping files. Outside of the overriding case, an exception is thrown if two or more named-native-querys with the same name are defined in one or across multiple mapping files.

sql-result-set-mapping

Full override

A sql-result-set-mapping is unique by name. The sql-result-set-mapping defined in the eclipselink-orm.xml will override a sql-result-set-mapping of the same name defined in other mapping files. Outside of the overriding case, an exception is thrown if two or more sql-result-set-mapping entities with the same name are defined in one or across multiple mapping files.


Mapped Superclasses

A mapped-superclass can be defined completely, or with specific elements to provide extensions to a mapped-superclass from another mapping file. Table 6-3 lists individual override and merging rules:

Table 6-3 Overriding and Merging Mapped Superclasses

entity-mappings/mapped-superclass Rule Description

id-class

Full override

If an id-class exists, then the eclipselink-orm.xml id-class setting overrides the existing setting, or creates a new id-class setting.

exclude-default- listeners

Full override

If an exclude-default-listeners exists, then the eclipselink-orm.xml exclude-default-listeners setting will be applied. If the exclude-default-listeners setting is not specified, it will not override an existing setting, that is essentially turning it off.

exclude-superclass- listeners

Full override

If an exclude-superclass-listeners setting exists, then the eclipselink-orm.xml exclude-superclass-listeners setting will be applied. If exclude-superclass-listeners setting is not specified, it will not override an existing setting, that is essentially turning it off.

entity-listeners

Merge and full override

If an entity-listeners setting exists, then the eclipselink-orm.xml entity-listeners setting will override and merge with an existing setting, or creates a new entity-listeners setting all together.

Note: An entity listener override must be complete. All lifecycle methods of that listener must be specified and no merging of individual lifecycle methods of an entity listener is allowed. The class name of the listener is the key to identify the override.

pre-persist

Full override

If a pre-persist setting exists, then the eclipselink-orm.xml pre-persist setting overrides the existing setting, or creates a new pre-persist setting.

post-persist

Full override

If a post-persist setting exists, then the eclipselink-orm.xml post-persist setting overrides the existing setting, or creates a new post-persist setting.

pre-remove

Full override

If a pre-remove setting exists, then the eclipselink-orm.xml's pre-remove setting overrides the existing setting, or creates a new pre-remove setting.

post-remove

Full override

If a post-remove setting exists, then the eclipselink-orm.xml's post-remove setting overrides the existing setting, or creates a new post-remove setting.

pre-update

Full override

If a pre-update setting exists, then the eclipselink-orm.xml's pre-update setting overrides the existing setting, or creates a new pre-update setting.

post-update

Full override

If a post-update setting exists, then the eclipselink-orm.xml's post-update setting overrides the existing setting, or creates a new post-update setting.

post-load

Full override

If a post-load setting exists, then the eclipselink-orm.xml's post-load setting overrides the existing setting, or creates a new post-load setting.

attributes

Merge and mapping level override

If the attribute settings (such as id, embedded-id, basic, version, many-to-one, one-to-many, or one-to-one) exist at the mapping level, then the eclipselink-orm.xml attributes merges or overrides the existing settings, else creates new attributes.

class

None


access

Full override

If an access setting exists, then the eclipselink-orm.xml's access setting overrides the existing setting, or creates a new access setting. It also overrides the default class setting.

metadata-complete

Full override

If a metadata-complete setting exists, then the eclipselink-orm.xml's metadata-complete setting will be applied. If metadata-complete setting is not specified, it will not override an existing setting, that is essentially turning it off.


Entity override and merging rules

An entity can be defined completely, or with specific elements to provide extensions to an entity from another mapping file. The following table lists individual override and merging rules:

Table 6-4 Overriding and Merging Entities

entity-mappings/entity Rule Description

table

Full override

The table definition overrides any other table setting (with the same name) for this entity. There is no merging of individual table values.

secondary-table

Full override

The secondary-table definition overrides another secondary-table setting (with the same name) for this entity. There is no merging of individual secondary-table(s) values.

primary-key-join-column

Full override

The primary-key-join-column(s) definition overrides any other primary-key-join-column(s) setting for this entity. There is no merging of the primary-key-join-column(s). The specification is assumed to be complete and these primary-key-join-columns are the source of truth.

id-class

Full override

If an id-class setting exists, then the eclipselink-orm.xml's id-class setting overrides the existing setting, or creates a new id-class .

inheritance

Full override

If an inheritance setting exists, then the eclipselink-orm.xml's inheritance setting overrides the existing setting, or creates a new inheritance setting.

discriminator-value

Full override

If a discriminator-value setting exists, then the eclipselink-orm.xml's discriminator-value setting overrides the existing setting, or creates a new discriminator-value setting.

discriminator-column

Full override

If a discriminator-column setting exists, then the eclipselink-orm.xml's discriminator-column setting overrides the existing setting, or creates a new discriminator-column setting.

sequence-generator

Full override

A sequence-generator is unique by name. The sequence-generator defined in eclipselink-orm.xml overrides sequence-generator of the same name defined in other mapping files. Outside of the overriding case, an exception is thrown if two or more sequence-generators with the same name are defined in one or across multiple mapping files.

table-generator

Full override

A table-generator is unique by name. The table-generator defined in eclipselink-orm.xml overrides table-generator of the same name defined in other mapping files. Outside of the overriding case, an exception is thrown if two or more table-generators with the same name are defined in one or across multiple mapping files.

named-query

Merge and full override

A named-query is unique by name. The named-query defined in eclipselink-orm.xml overrides any named-query of the same name defined in other mapping files. Outside of the overriding case, an exception is thrown if two or more named-query elements with the same name are defined in one or across multiple mapping files.

named-native-query

Merge and full override

A named-native-query is unique by name. The named-native-query defined in eclipselink-orm.xml overrides named-native-query of the same name defined in other mapping files. Outside of the overriding case, an exception is thrown if two or more named-native-query elements with the same name are defined in one or across multiple mapping files.

sql-result-set-mapping

Merge and full override

A sql-result-set-mapping is unique by name. sql-result-set-mapping defined in eclipselink-orm.xml overrides sql-result-set-mapping of the same name defined in other mapping files. Outside of the overriding case, an exception is thrown if two or more sql-result-set-mapping elements with the same name are defined in one or across multiple mapping files.

exclude-default-listeners

Full override

If an exclude-default-listeners setting exists, then the eclipselink-orm.xml's exclude-default-listeners setting will be applied. If an exclude-default-listeners setting is not specified, it will not override an existing setting, that is essentially turning it off.

exclude-superclass-listeners

Full override

If an exclude-superclass-listeners setting exists, then the eclipselink-orm.xml's exclude-superclass-listeners setting will be applied. If an exclude-superclass-listeners setting is not specified, it will not override an existing setting, that is essentially turning it off.

entity-listeners

Full override

If an entity-listeners setting exists, then the eclipselink-orm.xml's entity-listeners setting will override and merge with an existing setting, or creates a new entity-listeners setting all together.

Note: An entity listener override must be complete. All lifecycle methods of that listener must be specified and no merging of individual lifecycle methods of an entity listener is allowed. The class name of the listener is the key to identify the override.

pre-persist

Full override

If a pre-persist setting exists, then the eclipselink-orm.xml's pre-persist setting overrides the existing setting, or creates a new pre-persist setting.

post-persist

Full override

If a post-persist setting exists, then the eclipselink-orm.xml's post-persist setting overrides the existing setting, or creates a new post-persist setting.

pre-remove

Full override

If a pre-remove setting exists, then the eclipselink-orm.xml's pre-remove setting overrides the existing setting, or creates a new pre-remove setting.

post-remove

Full override

If a post-remove setting exists, then the eclipselink-orm.xml's post-remove setting overrides the existing setting, or creates a new post-remove setting.

pre-update

Full override

If a pre-update setting exists, then the eclipselink-orm.xml's pre-update setting overrides the existing setting, or creates a new pre-update setting.

post-update

Full override

f a post-update setting exists, then the eclipselink-orm.xml's post-update setting overrides the existing setting, or creates a new post-update setting.

post-load

Full override

If a post-load setting exists, then the eclipselink-orm.xml's post-load setting overrides the existing setting, or creates a new post-load setting.

attributes

Merge and mapping level override

If the attribute settings (id, embedded-id, basic, version, many-to-one, one-to-many, one-to-one) exist at the mapping level, then the eclipselink-orm.xml's attributes merges or overrides the existing settings, else creates new attributes.

association-override

Merge and mapping level override

If an association-override setting exists, then the eclipselink-orm.xml's association-override setting overrides the existing setting, or creates a new association-override setting.

name

Full override

If a name setting exists, then the eclipselink-orm.xml's name setting overrides the existing setting, or creates a new name setting.

class

None


access

Full override

If an access setting exists, then the eclipselink-orm.xml's access setting overrides the existing setting, or creates a new access setting. It also overrides the default class setting

metadata-complete

Full override

If a metadata-complete setting exists, then the eclipselink-orm.xml's metadata-complete setting will be applied. If a metadata-complete setting is not specified, it will not override an existing setting, that is essentially turning it off.


Embeddable

An embeddable can be defined wholly or may be defined so as to provide extensions to an embeddable from another mapping file. Therefore, we will allow the merging of that class' metadata. Table 6-4 lists the individual override rules Embeddable classes.

Table 6-5 Overriding and Merging Embeddable Classes

entity-mappings/ embeddable Rule Description

attributes

Override and merge

If the attribute settings (id, embedded-id, basic, version, many-to-one, one-to-many, one-to-one, many-to-many, embedded, transient) exist at the mapping level, then the eclipselink-orm.xml's attributes merges or overrides the existing settings, or creates new attributes.

class

None


access

Full override

If an access setting exists, then the eclipselink-orm.xml's access setting overrides the existing setting, or creates a new access setting. It also overrides the default class setting.

metadata-complete

Full override

If a metadata-complete setting exists, then the eclipselink-orm.xml's metadata-complete setting will be applied. If a metadata-complete setting is not specified, it will not override an existing setting, that is essentially turning it off.


Examples of Overriding and Merging

Example 6-1 Overriding/Merging Example 1

In this example, your EclipseLink project contains:

  • META-INF/orm.xml – Defines Entity A with the mappings b and c

  • META-INF/eclipselink-orm.xml – Defines Entity A with the mappings c and d

Results in:

  • Entity A containing:

    • mapping b (from orm.xml)

    • mappings c and d (from eclipselink-orm.xml)

Example 6-2 Overriding/Merging Example 2

In this example, your EclipseLink project contains:

  • META-INF/orm.xml – Defines Entity A with mappings b and c

  • META-INF/some-other-mapping-file.xml – Defines Entity B with mappings a and b

  • META-INF/eclipselink-orm.xml – Defines Entity A with the mappings c and d, and Entity B with mapping b and c

Results in:

  • Entity A containing:

    • mapping b (from orm.xml)

    • mappings c and d (from eclipselink-orm.xml)

  • Entity B containing:

    • mapping a (from some-other-mapping-file)

    • mappings b and c (from eclipselink-orm.xml)

Example 6-3 Overriding/Merging Example 3

In this example, your EclipseLink project contains:

  • META-INF/orm.xml – Defines Entity A with mappings b and c.

  • META-INF/eclipselink-orm.xml – Defines Entity A with mappings c and d.

  • META-INF/some-other-mapping-file.xml – Defines Entity A with mapping x.

Results in:

  • Entity A containing:

    • mapping b (from orm.xml)

    • mappings c and d (from eclipselink-orm.xml)

    • mapping x (from some-other-mapping-file.xml)

Example 6-4 Overriding/Merging Example 4

In this example, your EclipseLink project contains:

  • META-INF/orm.xml – Defines Entity A with mappings b and c.

  • META-INF/extensions/eclipselink-orm.xml – Defines defines Entity A with mappings c and d.

    Note: The file is added through a <mapping-file> tag in the persistence.xml file.

Results in an exception, due to conflicting specifications for mapping c.

Example 6-5 Overriding/Merging Example 5

In this example, your EclipseLink project contains:

  • META-INF/orm.xml – Defines Entity A with mappings b and c

  • META-INF/jpa-mapping-file.xml – Defines Entity A with mappings a and d

  • META-INF/extensions/eclipse-mapping-file.xml – Defines defines Entity A with mappings c and d

Results in an exception, due to conflicting specifications for mapping c or d (which ever is processed first).