Re: How to ensure data consistency?
From: Tony Andrews <andrewst_at_onetel.com>
Date: 7 Sep 2004 08:21:25 -0700
Message-ID: <chkjll$c0a_at_odbk17.prod.google.com>
Felix E. Klee wrote:
> However, there still needs to be validation (with triggers?) that the
Date: 7 Sep 2004 08:21:25 -0700
Message-ID: <chkjll$c0a_at_odbk17.prod.google.com>
Felix E. Klee wrote:
> However, there still needs to be validation (with triggers?) that the
> id's of the specified specialization are non null.
Check constraints can be used for that:
CHECK ((type = 'A' AND a_id IS NOT NULL) OR (type != 'A' AND a_id IS NULL)) Received on Tue Sep 07 2004 - 17:21:25 CEST