OK, I find the file "oracle-ds.xml". It should be the correct one. Besides I find some examples from the internet. The "persistence.xml" for Oracle looks as follow: | <persistence> | <persistence-unit name="ejb3trail"> | <jta-data-source>java:/OracleDS</jta-data-source> | <properties> | <property name="hibernate.hbm2ddl.auto" | value="create-drop"/> | </properties> | </persistence-unit> | </persistence> | But: 1. WHere can I put this file in my project? Under /META-INF/ ? Where the "persistence.xml" locates? 2. How can the program or the server knows where the file "oracle-ds.xml" locates? Should I change the <jta-data-source/> in "persistence.xml" as follow? | <persistence> | <persistence-unit name="ejb3trail"> | <jta-data-source>java:/oracle-ds</jta-data-source> | <properties> | <property name="hibernate.hbm2ddl.auto" | value="create-drop"/> | </properties> | </persistence-unit> | </persistence> | View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4149948#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...