Region restrictions (VOQL-TEG-1/AI#2)
benjamin.gufler at in.tum.de
Thu Oct 26 09:59:32 PDT 2006
I'd like to start the discussion on where to place the region restrictions.
I would prefer to have the region restrictions as an (optional?) part of
the WHERE, due to the following reasons:
* A region restriction is a selection criterion on for each single
tuple, and that's what the WHERE clause is intended for
* By taking REGION out of the WHERE, people would have to extend their
SQL parsers or - even worse - rewrite them. If region restrictions
look like function calls, an average SQL parser should work.
* One can write queries with muliple selection criteria. How should
queries containing some "normal" selections as well as region
restrictions in a separate REGION clause behave? Should the conditions
be connected by AND, OR, AND NOT, ...? And how about a single query
which should retrieve data from two distinct regions?
We would have to re-define a lot of syntactical as well as semantical
stuff which is already available in the WHERE clause and is well-known
to many people.
Dipl.-Inf. Benjamin Gufler Lehrstuhl Informatik III
Tel. +49 89 289-17276 Fax +49 89 289-17263
Boltzmannstr. 3, 85748 Garching Raum FMI 02.11.035
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