"CMP Entity Bean"? Is this a EJB 2.x question or a EJB3/JPA entity question? I'll assume the latter due to this forum being "EJB 3.0". See entityManager.merge() - it merges an unattached JPA entity bean meaning whatever values are in the bean will be put into the DB. It doesn't merge one particular field - the entire bean is merged. I don't know of a way to force only a single field (dirty or not) to be merged into the DB - I don't think its possible, short of you writing your own JPQL UPDATE query and executing that explicitly. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4138034#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...