Re: First order logic and SPARQL

Hi Axel & All --

Axel wrote *.....you don't want to translate your datalog program into
SPARQL and evaluate it with a sparql engine, that is likely not going to be
very efficient...*

So, does DERI have a datalog engine that's more efficient than SQL/SPARQL
over LARGE databases?

For datalog + NAF?

For stratified recursive datalog + NAF?

                                      -- Adrian

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Adrian Walker
Reengineering


On Tue, Sep 7, 2010 at 12:19 PM, Axel Polleres <axel.polleres@deri.org>wrote:

>
> On 5 Sep 2010, at 22:48, Bob MacGregor wrote:
>
> > My personal interest is in a query language for RDF that's easy to use,
> and, among other things,
> > has a negation operator that is intuitive.  If SPARQL 1.1 adds a negation
> operator, that is good to know.
> >
> > I would  be interested to learn of a datalog-with-negation implemented by
> translating to SPARQL,
> > since datalog and its variants is IMO intuitive.   Are the results that
> show a mapping between
> > a datalog variant and SPARQL just papers, or has someone actually
> implemented a Datalog-like
> > front end that translates to SPARQL?
> > I'd like to see that.  Note: Axel cites a paper that translates
> > in the other direction -- that's not what I'm after.
>
> Indeed, we have implemented only the other direction, SPARQL to Datalog, as
> a prototype plugin for the
> dlvhex system cf.
> http://dlvhex-semweb.svn.sourceforge.net/viewvc/dlvhex-semweb/
>
> Why would you need the translation of Datalog into SPARQL? That is
> something IMO just needed for the theoretical expressivity result, you dan't
> want to translate your datalog program into SPARQL and evaluate it with a
> sparql engine, that is likely not going to be very efficient...
>
> Axel
>
>
> > - Bob
>
>