Re: Does entity integrity imply entity identity?
From: rpost <rpost_at_pcwin518.campus.tue.nl>
Date: Mon, 3 Aug 2009 18:41:26 +0000 (UTC)
Message-ID: <h57b0m$gkd$3_at_mud.stack.nl>
Date: Mon, 3 Aug 2009 18:41:26 +0000 (UTC)
Message-ID: <h57b0m$gkd$3_at_mud.stack.nl>
David Portas wrote:
>It's more reasonable to say that a tuple can be understood to represent some
>fact which is normally assumed to be true. Entity = Thing. I don't see any
>special reason why a tuple MUST map to a "thing" (whatever that means) but
>if you find that interpretation useful then use it.
>
>The concept of "Entity Integrity" is not much more than a restatement of
>what a relation is anyway.
The source of these statements is, no doubt, page 146-147 of C. Date, 'Relational Database, Selected Writings', Addison-Wesley 1986. I'd love to quote it, but Date tends to use a lot of words, and I'm afraid it won't quality as fair use.
-- ReinierReceived on Mon Aug 03 2009 - 20:41:26 CEST