Exemplo de persistence

persistence.xml

<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_2_0.xsd"
	version="2.0">

	<persistence-unit name="testes">
		<provider>org.hibernate.ejb.HibernatePersistence</provider>
		
		<properties>
		
			<property name="hibernate.dialect" value="org.hibernate.dialect.MySQL5InnoDBDialect"/>
<!-- 			<property name="hibernate.hbm2ddl.auto" value="create"/> -->
			<property name="hibernate.hbm2ddl.auto" value="update"/>
			<property name="hibernate.show_sql" value="true"/>
			<property name="hibernate.format_sql" value="true"/>
			
			<property name="javax.persistence.jdbc.driver" value="com.mysql.jdbc.Driver"/>
			<property name="javax.persistence.jdbc.url" value="jdbc:mysql://localhost/testes"/>
			<property name="javax.persistence.jdbc.user" value="root"/>
			<property name="javax.persistence.jdbc.password" value=""/>
	        
		</properties>
	</persistence-unit>
	
</persistence>