EclipseLink Solutions Guide for EclipseLink
Release 2.4
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Configuring the persistence.xml File

The persistence.xml file is the deployment descriptor file for persistence using JPA. It specifies the persistence units and declares the managed persistence classes, the object/relation mapping, and the database connection details.

Main Tasks

To configure the persistence.xml file, the following tasks:

Task 1: Use the persistence.xml File

Example 17-2 illustrates a persistence.xml file for a Java SE platform configuration (that is, outside a container).

Example 17-2 A persistence.xml File Specifying the Java SE Platform Configuration

<persistence xmlns="" xmlns:xsi="" xsi:schemaLocation=" persistence_1_0.xsd" version="1.0">
    <persistence-unit name="my-app" transaction-type="RESOURCE_LOCAL">
            <property name="javax.persistence.jdbc.driver" value="oracle.jdbc.OracleDriver"/>
            <property name="javax.persistence.jdbc.url" value="jdbc:oracle:thin:@localhost:1521:orcl"/>
            <property name="javax.persistence.jdbc.user" value="scott"/>
            <property name="javax.persistence.jdbc.password" value="tiger"/>

Task 2: Instantiate EntityManagerFactory

An EntityManagerFactory provides an efficient way to construct EntityManager instances for a database. You can instantiate the EntityManagerFactory for the application (illustrated in Example 17-2) by using: