thanks a lot, that works fine now, and with innodb tables the referential integritay is not violated. But I´, not sure, how to act here correctly. I catch two (identical?) runtimeexceptions - why two? java.lang.RuntimeException: org.jboss.tm.JBossRollbackException: Unable to commit, tx=TransactionImpl:XidImpl[FormatId=257, GlobalId=nbmicho/143, BranchQual=, localId=143] status=STATUS_NO_TRANSACTION; - nested throwable: (javax.persistence.EntityExistsException: org.hibernate.exception.ConstraintViolationException: Could not execute JDBC batch update) | java.lang.RuntimeException: org.jboss.tm.JBossRollbackException: Unable to commit, tx=TransactionImpl:XidImpl[FormatId=257, GlobalId=nbmicho/143, BranchQual=, localId=143] status=STATUS_NO_TRANSACTION; - nested throwable: (javax.persistence.EntityExistsException: org.hibernate.exception.ConstraintViolationException: Could not execute JDBC batch update) before two ERRORS one with a stacktrace are reported ERROR [JDBCExceptionReporter] Cannot delete or update a parent row: a foreign key constraint fails (`test/benutzer_benutzergruppe`, CONSTRAINT `FKFB569FDA36A7B8DE` FOREIGN KEY (`benutzerGruppeListe_sid`) REFERENCES `benutzergruppe` (`sid`)) | ERROR [AbstractFlushingEventListener] Could not synchronize database state with session org.hibernate.exception.ConstraintViolationException: Could not execute JDBC batch update View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4020536#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...