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Re: definitions of queries vs. rules

From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
Date: Sat, 08 Sep 2001 10:44:45 -0400
To: jos.deroo.jd@belgium.agfa.com
Cc: eric@w3.org, www-rdf-rules@w3.org
Message-Id: <20010908104445B.pfps@research.bell-labs.com>
From: jos.deroo.jd@belgium.agfa.com
Subject: Re: definitions of queries vs. rules
Date: Sat, 8 Sep 2001 11:49:17 +0100

> 
> Peter F. Patel-Schneider wrote:
> > I worry that there are things in queries that should not be in rules.
> > Consider DB query systems like (gasp) SQL.  Do we want all the baggage of
> > something like SQL in the antecedants of rules?  Do we even want everything
> > in a cleaner rule algebra in the antecedants of rules?
> 
> Peter, do you have an example of such a clean rule algebra?

Not offhand, at least not an implemented one.  (Ask a DB person.) 

However the initial query explorations in relational DB theory resulted in
two different query formalisms (relational calculus and relational
algebra).  I view both of these formalisms as clean, and uncluttered, at
least in their initial form.  Some of the clutter was added later, with
such things as grouping.

Note that I am not directly arguing that an RDF (or DAML+OIL) query
language include all the constructs of even the standard relational
algebra, even if these were all to make sense for RDF (or DAML+OIL).

peter
Received on Saturday, 8 September 2001 10:45:47 GMT

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