Re: A pk is *both* a physical and a logical object.

From: Roy Hann <specially_at_processed.almost.meat>
Date: Tue, 17 Jul 2007 09:14:27 +0100
Message-ID: <7e2dncCYhYD45wHbRVnytAA@pipex.net>

"Brian Selzer" <brian_at_selzer-software.com> wrote in message news:1Pwmi.39574$Um6.32783_at_newssvr12.news.prodigy.net... [snip]
> In addition, the definition of a candidate key does not demand that its
> values rigidly designate individuals in the universe of discourse.

I've been waiting for someone else to pick up on this comment, but since they haven't I'm going to bite. When you talk about "individuals" here, do you intend that to be understood as "individual propositions"?

My layman's understanding is that the value of a candidate key most definitely *is* a unique identifier (and is irreducible).

Roy Received on Tue Jul 17 2007 - 03:14:27 CDT