Jared wrote: Oracle Apps - Not quite as sure about it, but I believe its origins predate the use of referential integrity in the database. I can confirm that; first apps development was in 1987-8 on Oracle 5.1 moving later to 6. No FKs even in the dictionary - and anyway configurable code combinations and flexfields (and the whole Application Foundation doodah) tend to push the work off the server into the application (even now). I've posted more here: http://preferisco.blogspot.com/2007/02/schema-models-fk-constraints-and-oracle.html if anyone is interested in industrial archeology on the subject. Regards Nigel