[redland-dev] Can Redland process transitive properties when running Sparql queries?

[Seref Arikan]

Thanks.
I think I can still use Redland within the postgresql server side functions
to access turtle responses from an external service which may do the
reasoning, and return results in turtle form.
In this case, I'd only be using it as a parser, but it may still help me in
some cases.

Kind regards
Seref


On Mon, Aug 27, 2012 at 6:29 PM, Slava Kravchenko <
slava.kravchenko at gmail.com> wrote:

> On Monday 27 Aug 2012 12:00:01 redland-dev-request at lists.librdf.org wrote:
> >    1. Can Redland process transitive properties when  running Sparql
> >       queries? (Seref Arikan)
>
> [...]
>
> > Greetings,
> > I need to process rdf in postgresql functions, and my plan is to use
> Python
> > wrappers for Redland to process turtle synax rdf, with some Sparql
> queries.
> >
> > Jena helps me on the client side by making use of transitive properties,
> so
> > when in my ontology a relation among nodes such as this one exists:
> >
> > A contains B contains C
> >
> > A Sparql query run by Jena for ?Node :contains ?childNode
> > returns both A B and A C pairs, due to transitive nature of contains
> > property. Protege can not make use of this information for example. so
> the
> > same Sparql query returns only A contains B when run from Protege.
> >
> > If I use Redland, would it be able to act in the same way as Jena? Your
> > response would help me skip installation time for the whole stack to find
> > the answers on my own and it would be appreciated a lot :)
>
> I believe the task of producing extra triples based on property
> transitivity
> (and similar cases) is the one that Redland "delegates" to the underlying
> storages. So, if your storage has reasoning capabilities (e.g. Virtuoso,
> although I couldn't make it work here), it will send the whole bunch, both
> real and "computed" RDF triples to Redland.
> So, ultimately, Redland cannot be compared to Jena - it's not a "semantic
> framework", but rather, a simple "interface" to a semantic storage.
>
> --
> Best regards,
>
> Slava Kravchenko
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>
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