I have already sent you the test program with our models. So if you launch the test prog and then look into the DB structure you can see, that these tables lack foreign keys: TagValue_MlTagValue ToolPanel_MlEnabledContext SecurityPrincipal_MlPrincipalOperation and many others derived from Multilink<,>. Moreover, some table have a foreign key for the Linked column, and some of them have NO FKs at all.