W3C home > Mailing lists > Public > www-rdf-rules@w3.org > September 2002

RE: Query use cases

From: Graham Klyne <GK@NineByNine.org>
Date: Mon, 23 Sep 2002 22:23:46 +0100
Message-Id: <5.1.0.14.2.20020923221720.0383a120@127.0.0.1>
To: "Seaborne, Andy" <Andy_Seaborne@hplb.hpl.hp.com>
Cc: "'RDF Rules'" <www-rdf-rules@w3.org>

At 10:03 AM 9/23/02 +0100, Seaborne, Andy wrote:
>One thing - with the rules you gave, don't you create duplicate statements?
>As a model is a set, don't you loose the multiple occurrences of the same
>value?  Of course, as you do variable bindings, you are OK here but it isn't
>pure RDF rules.

Ooops, you're right... if using the rules to construct a new graph.  Hmmm...

Semantically, treating the query as a "forall ... entailed by", that could 
be viewed as strictly correct (i.e. removing duplicates), given that such a 
query is for *membership* stripped of order.  I guess its another respect 
in which graph queries aren't always the same as entailment queries.  Also, 
the fact of sequential processing (implied by query with ordered results) 
means "stepping outside" the pure graph structure, I think.  But still 
important to do in some cases.

Conclusion:  it's not always satisfactory for the result of a query to be 
another graph?

Then:  rules aren't always a good way to formulate graph queries?

#g


-------------------
Graham Klyne
<GK@NineByNine.org>
Received on Monday, 23 September 2002 17:16:31 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Monday, 7 December 2009 10:53:09 GMT