Re: Lots of Idiotic Silly Braces?
From: paul c <toledobythesea_at_oohay.ac>
Date: Fri, 20 Jul 2007 22:23:20 GMT
Message-ID: <sBaoi.133437$NV3.45875_at_pd7urf2no>
Date: Fri, 20 Jul 2007 22:23:20 GMT
Message-ID: <sBaoi.133437$NV3.45875_at_pd7urf2no>
Brian Selzer wrote:
> ... Lending support to this is the fact that the duality of GROUP and
> UNGROUP does not hold for R. r UNGROUP S yields the relation value (call it
> r'), ...
Just an aside, regarding "duality", I sometimes think that it could be possible, if values were always sets of values, to avoid UNGROUP entirely and its distortion of certain single attribute relations. Projection might even be a special case of a GROUP that operated on sets. But this is just my peculiar view that conventional experts are likely to call twisted if not wacky.
p Received on Sat Jul 21 2007 - 00:23:20 CEST