Hi, Exactly, I would use a generated ID column for all of my entities. This makes it much easier to maintain the entities, because they all work the same way (call it a "design pattern" ;-) ). And if you use a web client, you have to use the IDs e.g. for lists or as hidden fields for forms, so you need a simple PK. Best regards Wolfgang View the original post : http://www.jboss.org/index.html?module=bb&op=viewtopic&p=4227235#... Reply to the post : http://www.jboss.org/index.html?module=bb&op=posting&mode=reply&a...