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Re: Grammatical Inconsistencies

From: Dawn M. Wolthuis <dwolt_at_tincat-group.com>
Date: Sun, 25 Apr 2004 10:27:34 -0500
Message-ID: <c6hb54$5rf$2@news.netins.net>


"Laconic2" <laconic2_at_comcast.net> wrote in message news:F9SdnRxVl5PWgRbd4p2dnA_at_comcast.com...
>
> > OK -- I thought all of these operations were on relations and returning
> > relations.
>
> A relation is a set. That is why operations on sets, such as union,
> intersection, etc. are operations on relations.
>

Yes, indeed. I do think I have cleared up my confusion on the terms. I was grouping all of the row-qualifiers in a select statement (those in a WHERE clause) together as a means of restricting the rows resulting from the cross-product, while it sounds like others think of the JOIN function as including those parts of the where clause that restrict the rows in such as way as to ensure you don't end up with a full cross-product in the result-set. I think that what I do and say "works" but is not quite aligned with the way others say it, so I will change my use of the terms to align and break up the row qualifiers into two sets -- those part of the join and those that are not.

Cheers! --dawn Received on Sun Apr 25 2004 - 10:27:34 CDT

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