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Home -> Community -> Usenet -> comp.databases.theory -> Re: Lots of Idiotic Silly Braces?
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 Fri Jul 20 2007 - 17:23:20 CDT
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