Re: Guessing?
From: Bob Badour <bbadour_at_pei.sympatico.ca>
Date: Tue, 08 Jul 2008 12:04:34 -0300
Message-ID: <48738203$0$4049$9a566e8b_at_news.aliant.net>
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> They are misconceived. The example strikes me as akin to Joe C's word
> games.
Date: Tue, 08 Jul 2008 12:04:34 -0300
Message-ID: <48738203$0$4049$9a566e8b_at_news.aliant.net>
paul c wrote:
>> "paul c" <toledobysea_at_ac.ooyah> wrote in message
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>>> However, I'm content to say that all three relations have the same >>> predicate, assuming no attribute renaming is involved in your >>> interpretation. I know many people say that the 'or' is introduced to >>> the predicate of R. I don't believe there is any law or principle, >>> including relational closure, that requires anybody to think this way. >>> >> >> How can they have the same predicate if they can have different >> extensions? That doesn't make any sense. >> ...
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> They are misconceived. The example strikes me as akin to Joe C's word
> games.
To answer Selzer's query, they have different external predicates but the same predicate as far as the DBMS can calculate. Received on Tue Jul 08 2008 - 17:04:34 CEST