userprefs relation to user fixed mapping;
1. 'userpreferences' (constraint) should depend on parent entity 'user'
2. 'user' and 'userpreferences' must have the same primary id, to fix the data, the userpreferences referenced from a user.preferences_id must have the id fixed accordingly. -> to be described!
->otherwise empty the userpreferencesbean table and drop the field preferences_id on the userbean table manually, all users preferences will be lost and have to be set again.