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Re: wrong example in the Fed.Ext. document

From: Eric Prud'hommeaux <eric@w3.org>
Date: Sat, 5 Jun 2010 04:53:43 -0400
To: Olaf Hartig <hartig@informatik.hu-berlin.de>
Cc: public-rdf-dawg-comments@w3.org
Message-ID: <20100605085341.GB2321@w3.org>
* Olaf Hartig <hartig@informatik.hu-berlin.de> [2010-06-04 14:37+0200]
> Hello,
> 
> The example in Section 2.1 of the Federation Extensions document [1] uses the 
> void vocabulary wrongly. The default graph in this example contains RDF 
> triples such as
> 
>   <http://GABABR1.example/SPARQL> a void:Dataset ;
>                               dcterms:subject entrez:h2550 .
> 
> The variable ?service of the example query is then mapped to URI 
> <http://GABABR1.example/SPARQL> and this URI is then used to identify a
> SPARQL service. That's not the meaning of void:Dataset. void:Dataset refers
> to a linked dataset and not to a SPARQL endpoint that exposes a linked 
> dataset.
> I propose to adjust the example as follows:
> 
> 1.) replace the abovementioned triples by the following (similar for the other 
> SPARQL services):
> 
>   <http://GABABR1.example/dataset> a void:Dataset ;
>                   dcterms:subject entrez:h2550 ;
>                   void:sparqEndpoint <http://GABABR1.example/SPARQL> .
> 
> 2.) replace the first triple patterns in the sample query by the following:
> 
>   # Find the service with the expertise.
>   ?dataset dcterms:subject ?gene ;
>                  void:sparqEndpoint ?service .
>   FILTER (?gene = entrez:h2550 || ?gene = entrez:h9568)

DONE V1.11

Does
  <x> dcterms:subject <p> ; void:sparqEndpoint <s> .
imply that the the query should look for a named graph à la
  SELECT ?y WHERE { GRAPH <x> { ?s <p> ?y } }
?

> BTW, the FILTER clause in the current example lacks a closing bracket.

DONE V1.11

> Greetings,
> Olaf
> 
> [1] http://www.w3.org/TR/2010/WD-sparql11-federated-query-20100601/

V1.11 of http://www.w3.org/2009/sparql/docs/fed/service#varService
should address this fixes. tx kindly!

-- 
-ericP
Received on Saturday, 5 June 2010 08:54:20 GMT

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