As you sead merge is used for detached objects and persist for atached ones. Short example for persist (update action) EntityManger em; ..... Tab02000 recentRecord = (Tab02000)em.find(Tab02000.class, key); .. do some changes to recentRecord em.persist(recentRecord); // in this case JPA will call update action because you are changing existing object Short example for merge EntityManger em; Tab02000 newRecord = new Tab02000(); ... set all values em.merge(newRecord); The second example is BAD PRACTISE of using JPA Jan View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4046303#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...