Hi kkangsar, 1) the DiscriminatorColumn name defaults to "DTYPE", so you need to specify the name only if you don't like the default ;-). 2) I don't have a simple answer this question ;-). Performance should not be an issue, because both approaches add the columns to the database table of the entity, so there are no additional entities. The approach with the @OneToOne relation ship (suggested by itsme) would result in an additional table. The benefit of the inheritance approach is that you don't need to add properties (access to your embedded object) to the subclass. So it saves you some lines of code ;-). Hope this helps Wolfgang View the original post : http://www.jboss.org/index.html?module=bb&op=viewtopic&p=4216895#... Reply to the post : http://www.jboss.org/index.html?module=bb&op=posting&mode=reply&a...