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Re: Compiling information from several different triplestores

From: Simon Schenk <sschenk@uni-koblenz.de>
Date: Tue, 05 May 2009 15:28:33 +0200
Message-ID: <4A003F01.1070705@uni-koblenz.de>
To: Paul Gearon <gearon@ieee.org>
CC: Nicolas Raoul <nicolas.raoul.lists@gmail.com>, semantic-web@w3.org
Hash: SHA1

> Mos triplestores will let you use graph URIs that contain CONSTRUCT
> queries on a SPARQL endpoint.

Wow, nice hack. :)

Regarding the question: Nicolas, I think you are looking for two things:
Distributed querying and owl:sameAs smushing.

For the first there are a couple of implementations (I am not claiming to be
complete here):

Our distributed SPARQL implementation for Sesame 2 [1] allows you to define
'magic' named graphs. Queries to these graphs will be evaluated locally or at
one or multiple remote SPARQL endpoints, depending on your endpoint configuration.

There is a FederationSail in Sesame 3 alpha [2]. I do not know the latest
version, but the one I looked at last was the most inefficient implementation
possible. ;-) To be honest I must say that in all implementations including ours
it is possible to write queries, which can hardly be evaluated distributedly.

DARQ [3] is based on Jena. In contrast to the other two, it does not guarantee
complete results AFAIC, but uses statistics about the data sources for optimization

As regards distributed owl:sameAs smushing, there are distributed reasoners,
which probably are overkill for your problem. Apart from that, I am not aware of
any existing implmentation.


[2] http://www.openrdf.org/
[3] http://darq.sourceforge.net/
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Received on Tuesday, 5 May 2009 13:29:12 UTC

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