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R:RDF query testcases?

From: Andrea Chiodi (E-mail) <andrea.chiodi@mail.inet.it>
Date: Fri, 17 Jan 2003 11:53:29 +0100
To: <www-rdf-rules@w3.org>
Message-ID: <000c01c2be16$ac0434f0$350164c0@MORGANA>

Hi. Apologies if I'm not catching the topic correctly (I've no time to read
carefully all the newsgroup mails).

I wrote some code in Jena to express a query as an RDF graph and to send it
to remote query processor that executes it.

Instead of "SELECT ?a,?b ... WHERE ... USING", I write a rdf:description of
the query, saying
"there is a query having a select with 2 variables, named a,b, this WHERE
clause, etc ...".
The receiving processor interprets the description of the query, composes a
regular SELECT clause, and executes it.
The answer also is returned as a rdf:description, saying:
"this is the answer to such a query, it was composed this way, it consists
in a result set with n results, with the given variables bound to these
values, ....."


Such a description helps me to realize some additional service, like:
- add other parameters to the query, not allowed by the SELECT syntax
- store the query for subsequent reuse
- identify the query (with a URI) as an existing 'desire' of somebody
- reason about the query (e.g. splitting it in subqueries)

As a ?side? effect, the query itself now is a resource in the semantic web,
so I could have another query looking for (a query looking for something). A
good tool for sellers, isn't? :-)


The experiment works pretty good, and I would like to compare it with other
similar experiments.

? Is it in the topic of this thread? (again apologies if it isn't)

? There exist some running activity on this approach in represesenting
queries ? Could you inform me about that ?

Thanks
---------------------------------------
Andrea Chiodi (andrea.chiodi@mail.inet.it)



> -----Messaggio originale-----
> Da: www-rdf-rules-request@w3.org
> [mailto:www-rdf-rules-request@w3.org]Per conto di Libby Miller
> Inviato: giovedi 16 gennaio 2003 18.06
> A: Jos De_Roo
> Cc: www-rdf-rules@w3.org
> Oggetto: Re: RDF query testcases?
>
>
>
>
> hi Jos!
>
> So, looking at
>
> http://www.agfa.com/w3c/euler/
>
> and particularly the questions like
>
> http://www.agfa.com/w3c/euler/gedcom-query.n3
>
> you're using n3 to describe an RDF graph and _interpreting_
> the graph as a query, is that right? like Pat Hayes said I think - an
> RDF graph with a question-mark at the end? So the graph means
> something
> different - a question, rather than a set of statements.
>
> I like this approach very much for testing especially (though I'd use
> N-triple rather than N3, there's not a big difference for something
> like this I don't think). The only issue I can see is that queries
> (although rarely in my experience) could have blank predicates, anbd
> predicates can't be bnodes in RDF as far as I know. Do you think this
> matters?
>
> For the results, cleverer backends might produce more results in for
> the same query, and we'd have to take this into account for describing
> the results.
>
> cheers,
>
> Libby
>
>
>
> On Thu, 16 Jan 2003, Jos De_Roo wrote:
>
> >
> > Hi Libby!
> >
> > good question; it seems to us that a query is simply
> > a set of triples where bnodes play the role of variables
> > we then basically can apply a resolution process
> >
> > [[[
> > The resolution process starts with a query. A query is a tripleset.
> > The query will be matched against the triplesets of the initial
> > graph G and against the rules. The set unifies with a rule when
> > one of the triples of the set unifies with the consequent of the
> > rule. The set unifies with another set if all triples in the set
> > unify with a triple of the other set. This can possibly be done
> > in different ways. The result of the unification of two triple
> > sets is a list of substitutionlists.
> > ]]]
> >
> http://www.agfa.com/w3c/2002/02/thesis/An_inference_engine_for
> _RDF.html
> > and this is work done by Guido Naudts in his master thesis
> >
> > we also have some running code at http://www.agfa.com/w3c/euler/
> > and some testcases starting at http://www.agfa.com/w3c/euler/etc5
> >
> > but there's still a lot to do...
> >
> > -- ,
> > Jos De Roo, AGFA http://www.agfa.com/w3c/jdroo/
> >
> >
> >
> >                     Libby Miller
> >                     <Libby.Miller@bris       To:
> www-rdf-rules@w3.org
> >                     tol.ac.uk>               cc:
> public-esw@w3.org
> >                     Sent by:                 Subject:
> RDF query testcases?
> >                     www-rdf-rules-requ
> >                     est@w3.org
> >
> >
> >                     2003-01-16 12:40
> >                     AM
> >
> >
> >
> >
> >
> >
> >
> >
> > Hi all
> >
> > We have some effort in SWAD-Europe [1] to write a document about RDF
> > query [see [2]]. Part of this will be FAQ-based - a start
> is here [3],
> > (and I'd be grateful for any FAQs or answers).
> >
> > The main reason for sending this message it because I've
> chatted to a
> > few people who feel that a collection of RDF query
> testcases would be a
> > useful thing to have, and I can put some effort into this -
> maybe as a
> > minimum, finding out what's already available, and maybe
> look into some
> > ways of enabling one query language implementation to use another's
> > testcases.
> >
> > So, would anyone out there like to share their test and their
> > experiences of writing them? I can infer that Jena and 4suite have
> > them; I think Mozilla has some too. I've got some here for Inkling:
> >
> > http://swordfish.rdfweb.org/rdfquery/tests/
> > http://swordfish.rdfweb.org/rdfquery/rdf/
> > http://swordfish.rdfweb.org/rdfquery/queries/
> >
> > Basically the test scripts read in
> > http://swordfish.rdfweb.org/rdfquery/rdf/query-results-manifest.rdf
> >
> > which specifies the RDF/XML file to pull in, the query to
> use and the
> > expected number of rows in the resulting table. So it's only a very
> > basic test of whether the query engine is functioning.
> >
> > Any more? Any thoughts?
> >
> > cheers,
> >
> > Libby
> >
> > [1] http://www.w3.org/2001/sw/Europe/
> > [2]
http://www.w3.org/2001/sw/Europe/plan/workpackages/live/esw-wp-7.html
> [3] http://www.w3.org/2001/sw/Europe/reports/rdf_ql_comparison_report/
>
>
>
>
>
>
>
>
Received on Saturday, 18 January 2003 05:47:45 GMT

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