On Sat, 26 Jun 2004, elein wrote: > Can someone explain the reasoning behind not allowing > a user table to contain a foreign key of a system table? > > For example: > > create table myusers ( > login text references pg_catalog.pg_shadow(usename), > ... > ); > > Fails with a message about using system catalogs. > Using pg_user fails because it is a view and not a table. > > Is it because updates to the catalogs can be done outside > of transactions? Is that a good enough reason?
I believe it's because changes to at least some of the system catalogs can be done without going through the entire sequence that an update/insert/delete statement would (ie, the triggers might not be fired thus meaning the constraint isn't properly checked). ---------------------------(end of broadcast)--------------------------- TIP 1: subscribe and unsubscribe commands go to [EMAIL PROTECTED]
