Path: utzoo!attcan!uunet!cs.utexas.edu!swrinde!ucsd!rutgers!netnews.upenn.edu!grad2.cis.upenn.edu!aaron
From: aaron@grad2.cis.upenn.edu (Aaron Watters)
Newsgroups: comp.databases
Subject: outerjoins
Message-ID: <28462@netnews.upenn.edu>
Date: 14 Aug 90 13:59:45 GMT
Sender: news@netnews.upenn.edu
Reply-To: aaron@grad2.cis.upenn.edu.UUCP (Aaron Watters)
Organization: University of Pennsylvania
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The various varieties of outerjoins are interesting operations.
In particular, they are interesting because they don't act like
relational operations in the sense that
	(r outerjoin s) minus t
or	(r outerjoin s) join t
don't seem to be well defined.  To be fanciful, I would hypothesize
that the outerjoin lies on the fringes of the standard relational paradigm,
and its usefulness indicates useful directions in which the paradigm
should be broadened.  Comments?

What are interesting (simple) examples of the uses for outerjoins? -aaron