Re: Relation Schemata vs. Relation Variables

From: J M Davitt <jdavitt_at_aeneas.net>
Date: Wed, 06 Sep 2006 02:38:28 GMT
Message-ID: <EwqLg.84$MD6.80@tornado.ohiordc.rr.com>

JOG wrote:
> Brian Selzer wrote:
>

>>[snip]
>>This is a contradiction.  A transition constraint must either be able to
>>pair the elements of two relations for comparison or be given a set of pairs
>>to compare.

>
>
> Ok, what on earth is a transition constraint then? A transition occurs
> when an 'entity' changes. In contrast a fact cannot 'change'. It is
> either true or not, and that is that.
>
> I conclude therefore that transitions are associated with entities
> alone, as are constraints upon them. The RM is unconcerned with
> 'entities' and hence is equally unconcerned with transition
> constraints.
>
> This whole question is therefore moot.

What he said.

> The rest of this argument is based on a confused assumption AFAICT.

That part, too. Received on Tue Sep 05 2006 - 21:38:28 CDT