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Re: AW: SPARQL/SQL/D2R/dbview (un)scheduled topic chat 8 Jun minutes/record

From: Axel Polleres <axel.polleres@urjc.es>
Date: Tue, 20 Jun 2006 14:17:14 +0200
Message-ID: <4497E74A.2070900@urjc.es>
To: Chris Bizer <chris@bizer.de>
CC: 'Dan Brickley' <danbri@danbri.org>, 'Chris Bizer' <bizer@zedat.fu-berlin.de>, 'Dan Connolly' <connolly@w3.org>, public-sparql-dev@w3.org, 'Tim Berners-Lee' <timbl@w3.org>, "'Seaborne, Andy'" <andy.seaborne@hp.com>, 'Eric Prud'hommeaux' <eric@w3.org>, 'Elias Torres' <eliast@us.ibm.com>, 'Chimezie Ogbuji' <ogbujic@bio.ri.ccf.org>, 'Richard Cyganiak' <richard@cyganiak.de>, danny.ayers@gmail.com, bastian@quilitz.de

Chris Bizer wrote:
> Hi all,
> 
> Dan Brickley, Bastian Quilitz (HP Labs Bristol), Alex Polleres (Universidad
                                                    ^^^^ Axel ;-)

> Rey Juan Carlos) and I meet for lunch at ESWC Tuesday and discussed about
> database to RDF mapping, SPARQL endpoint descriptions and federated SPARQL
> queries.
> 
> Dan Brickley has some connections to the MusicBrainz people and we discussed
> mapping their database to an SPARQL-endpoint, which might inspire some nice
> mashups. The problem is that D2R server currently answers all queries
> (including dump database) which opens up a wide gate for denial-of-service
> attacks. We want to fix this in the next version. Anybody good ideas for a
> "query capability restriction language"? 
> 
> Bastian Quilitz has implemented a version of ARQ which routes queries to
> different data sources. His code supports distributed joins. He is also
> working on a format for SPARQL-endpoint descriptions and promised to publish
> something about his work soon. He knows Richard Cyganiak and they want to
> hack a demo that answers SPARQL queries over several relational database
> which are mapped to SPARQL endpoints using D2R server. Maybe we can also
> reuse some of his work on SPARQL-endpoint descriptions for restricting query
> capabilities.

Dear all,

Just to wrap up my personal interest in this work:
  We are currently working on an EU project which shall eventually rely 
on  distributed RDF stores for service communication, where this work 
would fit, and I could imagine fruitful cross-fertilization:
  http://www.tripcom.org
Particularly,  I am personally  interested in the connection SPARQL & 
Rules, being a member of the RIF WG.

We briefly talked about optimizing distributed query plans and I 
promised to send some pointers on this.
  The work which might be relevant/interesting here is:

  Josť Luis Ambite, Craig A. Knoblock. Flexible and Scalable Query 
Planning in Distributed and Heterogeneous Environments. AIPS 1998.

These people also gave a full-day tutorial on this topic at ICAPS 2004:
http://www-rcf.usc.edu/~skoenig/icaps/icaps04/tutorial3.html


> We further discussed requirements for a SPARQL endpoint description language
> (there seams to be plenty).

This is a very interesting topic, particularly describing e.g. local 
completeness of a source on particular information etc., see above 
links, which can be exploited for query plan generation. I plan to 
investigate whether how the described techniques allow for easy adoption
in large scale web environment.

best,
Axel

> As TODOs, we agreed that everybody should add requirements and related work
> to the following two wiki pages:
> 
> Database to RDF mapping http://esw.w3.org/topic/RdfAndSql
> SPARQL endpoint description
> http://esw.w3.org/topic/SparqlEndpointDescription
> 
> Later, we want to aggregate the requirements into a set of evaluation
> criteria for comparing the different approaches.
> 
> Dan, Alex and Bastian, did I forget something?
> 
> Cheers
> 
> Chris
> 


-- 
Dr. Axel Polleres
email: axel@polleres.net  url: http://www.polleres.net/
Received on Tuesday, 20 June 2006 12:23:09 GMT

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