Re: Is it Possible to Enforce This Relationship at the DB Level?

From: David Cressey <>
Date: Tue, 16 Oct 2007 12:36:56 GMT
Message-ID: <If2Ri.1115$GM2.952_at_trndny02>

"David Portas" <> wrote in message
> On 15 Oct, 22:59, dutone <> wrote:
> >
> > I'd like to enforce this based on the data model and its
> > relationships.
> > Although to me, it doesn't seem possible without an additional layer
> > of logic.
> > The need for a check assertion in a RDMS tells me that cerain
> > cituations must be enforced at a higher level. This is one of them I
> > guess.
> >
> Maybe your definition of a data model differs from mine. All such
> constraints are surely part of that model irrespective of what syntax
> the DBMS uses.
> If you have some particular DBMS in mind then maybe someone will have
> other suggestions about features supported by that product. Perhaps a
> redesign would also be possible but I'm reluctant to begin a design-by-
> newsgroup exercise.
Very good point. Design-by-newsgroup has almost always been based on flawed analysis.

Second, "enforcing this based on the model" is clearly an implementation issue, not a modeling issue. Received on Tue Oct 16 2007 - 14:36:56 CEST

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