Re: ID field as logical address
From: none <rp_at_raampje.>
Date: 07 Jun 2009 20:29:56 GMT
Message-ID: <4a2c2344$0$6254$703f8584_at_news.kpn.nl>
Date: 07 Jun 2009 20:29:56 GMT
Message-ID: <4a2c2344$0$6254$703f8584_at_news.kpn.nl>
Brian Selzer wrote:
>[...] But in
>theory, using just the before and after values of the Bins relvar, how can
>one declare the transition constraint?
You're right that it's impossible without making some further assumption, Designing your database schema to have immutable keys is clearly preferable but I agree with you that in some situations this isn't possible. Changing the situation to allow it would still be a good idea, as I think your bins example clearly shows: it's a design begging for trouble.
-- ReinierReceived on Sun Jun 07 2009 - 22:29:56 CEST