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Re: First order logic and SPARQL

From: Axel Polleres <axel.polleres@deri.org>
Date: Tue, 7 Sep 2010 19:53:19 +0100
Cc: <semantic-web@w3.org>, <public-sparql-dev@w3.org>
Message-Id: <69ECDD1A-D51C-4EB3-815E-4AF235957C6A@deri.org>
To: "Adrian Walker" <adriandwalker@gmail.com>

On 7 Sep 2010, at 19:13, Adrian Walker wrote:

> 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?


"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..."

Sorry, my bad/momentary brain outgage, see last mail (it's been a long day today, sorry, ;-) )...  the dlvdb system [1] which I mentioned there, does exactly that... however, for recursive rules they still use the datalog engine's machinery, since recursive views are typically not implemented very efficiently within SQL DBs.

cheers,
Axel

1. G. Terracina, N. Leone, V. Lio, C. Panetta, Experimenting with recursive queries in database and logic programming systems, Theory and Practice of Logic Programming (TPLP), 8(2), 129-165, 2008. (Paper listed in the Computing Research Repository (CoRR) - http://arxiv.org/corr/home - CoRR number: 0704.3157).



>                                       -- Adrian
> 
> Internet Business Logic
> A Wiki and SOA Endpoint for Executable Open Vocabulary English Q/A over SQL and RDF
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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
> 
> 
Received on Tuesday, 7 September 2010 18:53:55 GMT

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