Re: Columns without names

From: paul c <toledobythesea_at_oohay.ac>
Date: Sat, 16 Sep 2006 15:05:11 GMT
Message-ID: <HoUOg.546926$iF6.172465_at_pd7tw2no>


JOG wrote:
> David Cressey wrote:

>> "JOG" <jog_at_cs.nott.ac.uk> wrote in message
>> news:1158372047.852132.130270_at_p79g2000cwp.googlegroups.com...
>>
>>> These are potentially different statements to those such as "There is a
>>> person, Sally" because the latter is stating "There is a person where
>>> name:Sally". The values held in the former assertions have no
>>> discernable attribute name - rather than a tuple such as {
>>> (name:Sally), (age:28)} I just have { (7) } or { (b) }.
>> Actually, "7" is the name of a number, and not the number itself.

>
> Is it? Could you expand on that, as I'm not sure there isn't a
> difference? Is that the same for the letter b? I think at some level I
> am mulling over the concept of atomicity (or non-decomposability) here,
> and how a domain might be defined as a relation itself.
>

I think you are indeed talking about different 'levels', ie., picking a different starting point than conventional theory, say Codd's theory, takes. When you do this, all bets are off. In some other thread, others have said better than I could that starting with a domain of true and false values, one could construct many other domains but that in practical terms this is somewhat pointless since mathematicians have already done it, on paper at least.

I think Codd was advocating taking the practical domain values and some identity test as given, ie., as a starting point. The rest of his theory has to do with formulating and manipulating those givens. You could use his theory to construct arbitrary domains, but that would involve a dbms engine at a lower/deeper philosophical level than the applications most dbms users want.

So when you talk this way, I think you are really advocating a point of view that discards the gist of his theory. If that's so, I would think one is obligated to construct a different theory that takes a different starting point.

p Received on Sat Sep 16 2006 - 17:05:11 CEST

Original text of this message