The META-INF/persistence.xml configuration file in the ejb/src/main/resources folder in the jboss-ejb3-ejb subproject was created when we created the Java EE project. The persistence.xml specifies a persistence provider to be used to map object/relational entities to the database. Specify that, the persistence unit is using the persistence-unit element. Set the transaction-type to JTA (the default value). Specify the persistence provider as the Hibernate persistence provider: org.hibernate.ejb.HibernatePersistence. Set the jta-data-source element value to the java:jboss/datasources/MySQLDS data source, which we created earlier. Specify the entity classes using the class element. The DDL generation strategy is set to create-drop using the hibernate.hbm2ddl.auto property, which automatically validates or exports the DDL schema to the database, when the SessionFactory class is created. With the create-drop strategy, the required tables are created and dropped when the SessionFactory is closed. The hibernate.show_sql property is set to false. Setting it to true implies that all SQL statements be the output, which is an alternative method to debug. The hibernate.dialect property is set to org.hibernate.dialect.MySQLDialect for MySQL Database. Other Hibernate properties (http://docs.jboss.org/hibernate/orm/3.3/reference/en/html/session-configuration.html) can also be specified as required. The persistence.xml configuration file is listed in the following code:

<?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" version="2.0" xsi:schemaLocation="         http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd">
  <persistence-unit name="em" transaction-type="JTA">
    <provider>org.hibernate.ejb.HibernatePersistence</provider>
    <!-- If you are running in a production environment, add a managed data source, the example data source is just for development and testing! -->
    <jta-data-source>java:jboss/datasources/MySQLDS</jta-data-source>
    <class>org.jboss.ejb3.model.Article</class>
    <class>org.jboss.ejb3.model.Catalog</class>
    <class>org.jboss.ejb3.model.Edition</class>
    <class>org.jboss.ejb3.model.Section</class>
    <properties>
      <!-- Properties for Hibernate -->
      <property name="hibernate.hbm2ddl.auto" value="create-drop" />
      <property name="hibernate.show_sql" value="false" />
      <property name="hibernate.dialect" value="org.hibernate.dialect.MySQLDialect" />
    </properties>
  </persistence-unit>
</persistence>

The JPA specification does not mandate a persistence provider to create tables with the hibernate.hbm2ddl.auto property set to create-drop or create. Hibernate persistence provider supports creating tables. In addition to the entity tables, some additional tables (such as the join tables and the sequence table) are created by the Hibernate persistence provider.