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Difference between revisions of "EclipseLink/UserGuide/JPA/Basic JPA Development/Configuration/JPA/persistence.xml"
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In this file, you can specify the vendor extensions that this reference describes by using a '''<properties>''' element. | In this file, you can specify the vendor extensions that this reference describes by using a '''<properties>''' element. | ||
− | + | <source lang="xml"> | |
<persistence-unit name="default" transaction-type="RESOURCE_LOCAL"> | <persistence-unit name="default" transaction-type="RESOURCE_LOCAL"> | ||
<provider>org.eclipse.persistence.jpa.PersistenceProvider</provider> | <provider>org.eclipse.persistence.jpa.PersistenceProvider</provider> | ||
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</properties> | </properties> | ||
</persistence-unit> | </persistence-unit> | ||
− | </source | + | </source> |
==How to Specify the Persistence Unit Name== | ==How to Specify the Persistence Unit Name== | ||
− | If you are developing your application in a Java EE environment, ensure that the persistence unit name is unique within each module. For example, you can define only one persistence unit with the name | + | If you are developing your application in a Java EE environment, ensure that the persistence unit name is unique within each module. For example, you can define only one persistence unit with the name '''EmployeeService'' in an '''emp_ejb.jar''' file. The following example shows how to define the name of the persistence unit: |
− | <persistence-unit name="EmployeeService"> | + | <persistence-unit name="EmployeeService"> |
For more information, see Section 6.2.1.1 "name" of the JPA Specification. | For more information, see Section 6.2.1.1 "name" of the JPA Specification. |
Revision as of 11:15, 15 June 2010
persistence.xml
A persistence unit configures various details that are required when you acquire an entity manager. You specify a persistence unit by name when you acquire an entity manager factory.
You configure persistence units in the JPA persistence descriptor file: persistence.xml. This file should be in the meta-inf/ directory of your persistence unit jar file, or classpath.
In this file, you can specify the vendor extensions that this reference describes by using a <properties> element.
<persistence-unit name="default" transaction-type="RESOURCE_LOCAL"> <provider>org.eclipse.persistence.jpa.PersistenceProvider</provider> <!-- By default your mappings can be defined in orm.xml file, --> <!-- which is discovered automatically. --> <mapping-file>META-INF/my-mappings.xml</mapping-file> ... <jar-file>my-additional-jar.jar</jar-file> ... <!-- Enables auto discovery of persistent classes, --> <!-- otherwise they must be listed using <class> --> <exclude-unlisted-classes>false</exclude-unlisted-classes> <properties> ... </properties> </persistence-unit>
How to Specify the Persistence Unit Name
If you are developing your application in a Java EE environment, ensure that the persistence unit name is unique within each module. For example, you can define only one persistence unit with the name EmployeeService in an emp_ejb.jar' file. The following example shows how to define the name of the persistence unit:
<persistence-unit name="EmployeeService">
For more information, see Section 6.2.1.1 "name" of the JPA Specification.
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