Region restrictions (VOQL-TEG-1/AI#2)

[Benjamin Gufler]

Dear all,

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.

Cheers,
	Benjamin
-- 
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