Thanks a lot for the help. In the DB there are no foreign keys. Inspecting the Database, I saw, that the tabletype is MyISAM whitch I think doenot support foreign keys. How can I tell Hibernate to create the tables with type innodb? I tried dropping the tables. The uniqueconstraint, which wasn´t working before now works correct, the referential integrity not. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4020132#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...