Re: Database design, Keys and some other things

Gene Wirchenko wrote:
> On 1 Oct 2005 09:52:49 -0700, "Marshall Spight"
> <marshall.spight_at_gmail.com> wrote:
>
> [snip]
>
> >We were discussing whether there was a difference between
> >the natures of external ids vs. surrogate keys. What is
> >essential to this question is what their nature is. Generally
> >we do not regard context-specific considerations as essential.
>
> Was it murder or self-defence? Context.

There are many domains where this sort of context is relevant. Mathematics is not on the list, however. Whether a number is an integer or not is not context-dependent. Given what's been said on this thread so far about the difference, it looks to me similar to the difference between the primary key and other candidate keys; a psychological, non-mathematical, contextual difference.

This is not to say that it's irrelevant. There may be significant software engineering and/or usability issues involved. But it does say that the difference has no particular theoretical basis.

Marshall Received on Tue Oct 04 2005 - 01:56:14 CEST