Re: Grammatical Inconsistencies
Date: Sun, 25 Apr 2004 10:27:34 -0500
Message-ID: <c6hb54$5rf$2_at_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 - 17:27:34 CEST