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Re: Alternative Syntaxes for BGPs

From: Paul Gearon <gearon@ieee.org>
Date: Thu, 29 Oct 2009 21:11:04 -0400
Message-ID: <a25ac1f0910291811i9909519lf51004ee40babd8a@mail.gmail.com>
To: Birte Glimm <birte.glimm@comlab.ox.ac.uk>
Cc: SPARQL Working Group <public-rdf-dawg@w3.org>
I'll respond directly to Birte's email.

On Thu, Oct 29, 2009 at 2:48 PM, Birte Glimm
<birte.glimm@comlab.ox.ac.uk> wrote:
> Hi all,
> this is mainly motivated from entailment regimes, but might be of
> interest to others, so I didn't prefix the subject of the email.
> I would like to suggest alternative syntaxes for BGPs because in
> particular for OWL with Direct Semantics triple syntax can be very
> long and not very intuitive. E.g.,
> SELECT ?p WHERE { ?p a _:x . _:x a owl:restriction . _:x
> owl:onProperty :hasChild . _:x owl:SomeValuesFrom :Male . }
> asks for things that have a male child. In OWL Functional-Style Syntax
> (used throughout the OWL 2 spec) that would be
> SELECT ?p WHERE { ClassAssertion(ObjectSomeValuesFrom(:hasChild :Male) ?p) . }
> That is not much shorter, but probably more intuitive for OWL folks.
> Each such BGP can directly be translated into triples and for
> functional-style syntax, for example, a mapping to triples is part of
> the OWL 2 spec.
> Now there are at least two possibilities. One could allow SPARQL
> queries with BGPs in non-triple syntax (no mandatory support from
> SPARQL systems) and another one is that SPARQL BGPs are always
> triples, but query interfaces could support different BGP syntaxes and
> translate them to triples before issuing the query.
> In any case, how does the group feel about adding a section about
> alternative syntaxes to the entailment regimes document?

I like this, and believe that it (or something like it) is essential
for OWL queries. Even if I didn't think that before, then I certainly
felt that way by the end of OWLED.

That said, SPARQL is a query language for RDF, and I'd like to see
that focus continue. I also agree with Andy's points about us being
time poor.

I'm also uncomfortable with the "fallback until something works"
approach. Keeping it out of SPARQL and in it's own spec makes me much
more comfortable. It seems like an easy (and worthwhile) extension.

Paul Gearon
Received on Friday, 30 October 2009 01:11:37 UTC

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