Re: foreign key constraint versus referential integrity constraint
From: Marshall <marshall.spight_at_gmail.com>
Date: Sun, 25 Oct 2009 15:05:31 -0700 (PDT)
Message-ID: <386975f9-472c-4184-8661-5c3d1e2f7621_at_r24g2000prf.googlegroups.com>
Date: Sun, 25 Oct 2009 15:05:31 -0700 (PDT)
Message-ID: <386975f9-472c-4184-8661-5c3d1e2f7621_at_r24g2000prf.googlegroups.com>
On Oct 24, 10:53 am, Keith H Duggar <dug..._at_alum.mit.edu> wrote:
>
> Anyhow, the question here is not one of our imagination but rather
> simply this: if it makes sense for the RM to support constraints
> on relational /values/ (taken on by variables) why does it not
> make sense to support constraints on relational /expressions/?
> That is a question of general principle not specific design.
This question, it seems to me, is clear and to the point. And I would answer it by saying that we shouldn't really even make the distinction! (At least not formally.)