At deployment time the Enterprise Server will automatically drop and create the database tables used by roster. This is done by setting the toplink.ddl-generation property to drop-and-create-tables in persistence.xml.
<?xml version="1.0" encoding="UTF-8"?> <persistence xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd" version="1.0"> <persistence-unit name="em" transaction-type="JTA"> <jta-data-source>jdbc/__default</jta-data-source> <properties> <property name="toplink.ddl-generation" value="drop-and-create-tables"/> </properties> </persistence-unit> </persistence>
This feature is specific to the Java Persistence API provider used by the Enterprise Server, and is non-portable across Java EE servers. Automatic table creation is useful for development purposes, however, and the toplink.ddl-generation property may be removed from persistence.xml when preparing the application for production use, or when deploying to other Java EE servers.