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RE: Usage of datasets and graphs in triple store

From: Mark Wallace <mark.wallace@semanticarts.com>
Date: Thu, 15 Mar 2018 16:42:04 +0000
To: Mikael Pesonen <mikael.pesonen@lingsoft.fi>, "semantic-web@w3.org" <semantic-web@w3.org>
Message-ID: <BYAPR11MB2856497211C5508A1215CF03E1D00@BYAPR11MB2856.namprd11.prod.outlook.com>
The FROM clause brings in an RDF graph from a URL, so if the external triple store provides a URL to a data set, then it's possible. 

For example, the RDF4J triple store exposes an HTTP API to access RDF statements in any of its "repositories", so you could do something like:

   select * 
   FROM  <http://localhost:8080/rdf4j-server/repositories/myRepo/statements>   
   where . . .

So it's definitely possible.  

SERVICE would seem more efficient than fetching all of the repository statements if the data set is large. 

 -Mark

-----Original Message-----
From: Mikael Pesonen <mikael.pesonen@lingsoft.fi> 
Sent: Wednesday, March 14, 2018 10:39 AM
To: semantic-web@w3.org
Subject: Usage of datasets and graphs in triple store


Hi,

what would be good reasons to split data to different graphs and also into different datasets?

About sparql FROM clause, is it possible to fetch data from external triple store, or is SERVICE method for that only?

Thank you

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Received on Friday, 16 March 2018 07:58:42 UTC

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