Re: Foreign superkey support

"Jon Heggland" <jon.heggland_at_idi.ntnu.no> wrote in message news:ebcmje$slu$1_at_orkan.itea.ntnu.no...
> David Cressey wrote:
> > The above surprises me. I had thought that the CHECK constraint in
Rdb/VMS
> > was sufficiently general to express any and all Boolean conditions, and
> > that the CHECK constraint would have been covered by numerous
competitors.
> > Am I wrong about the span of the CHECK constraint? Or do most DBMS's
lack
> > support for the CHECK constraint?
>
> What precisely do you mean by a CHECK constraint? The "CHECK" keyword is
> used for several different kinds of constraints in SQL, with varying
> degrees of support/implementation.
> --

I was unaware of the differences you describe.

The closest I can come to being specific is the CHECK constraint as implemented in Rdb.

> Jon
Received on Thu Aug 10 2006 - 12:48:23 CEST