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Re: DBpedia SPARQL Endpoint and Transitive Queries

From: Alexandre Passant <alexandre.passant@deri.org>
Date: Thu, 8 Oct 2009 16:28:01 +0100
Cc: "dbpedia-discussion@lists.sourceforge.net" <dbpedia-discussion@lists.sourceforge.net>, "public-lod@w3.org" <public-lod@w3.org>
Message-Id: <69373277-678B-44E5-9ECE-F5E2AE5E6C0B@deri.org>
To: Kingsley Idehen <kidehen@openlinksw.com>
Hi,

On 8 Oct 2009, at 16:09, Kingsley Idehen wrote:

> All,
>
> The intersection of Leigh Dodds SPARQL extensions survey [1],  
> imminent official release of Virtuoso 6.0 (DBpedia basic and Live  
> already use this, ditto LOD Cache, and B3S public endpoints), and an  
> old post by Bernard Vatant re. skos:broader, has lead to this  
> simple, but powerful example of  Virtuoso's Transitive Option  
> extension for SPARQL :
>
> #Transitive Option Off
>
> PREFIX p: <http://dbpedia.org/property/>
> PREFIX dbpedia: <http://dbpedia.org/resource/>
> PREFIX category: <http://dbpedia.org/resource/Category:>
> PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
> PREFIX skos: <http://www.w3.org/2004/02/skos/core#>
> PREFIX geo: <http://www.georss.org/georss/>
>
> SELECT DISTINCT ?m ?n ?p ?d
> WHERE {
>  ?m rdfs:label ?n.
>  ?m skos:subject ?c.
>  ?c skos:broader category:Churches_in_Paris.
>  ?m p:abstract ?d.
>  ?m geo:point ?p
> FILTER ( lang(?n) = "fr" )
> FILTER ( lang(?d) = "fr" )
> }
>
> #Transitive Option On
>
> PREFIX p: <http://dbpedia.org/property/>
> PREFIX dbpedia: <http://dbpedia.org/resource/>
> PREFIX category: <http://dbpedia.org/resource/Category:>
> PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
> PREFIX skos: <http://www.w3.org/2004/02/skos/core#>
> PREFIX geo: <http://www.georss.org/georss/>
>
> SELECT DISTINCT ?m ?n ?p ?d
> WHERE {
>  ?m rdfs:label ?n.
>  ?m skos:subject ?c.
>  ?c skos:broader category:Churches_in_Paris OPTION (TRANSITIVE).
>  ?m p:abstract ?d.
>  ?m geo:point ?p
> FILTER ( lang(?n) = "fr" )
> FILTER ( lang(?d) = "fr" )
> }
>
>

As skos:broader is not transitive [1] but its superproperty  
skos:broaderTransitive is, shouldn't the second query be

  ?c skos:broaderTransitive category:Churches_in_Paris OPTION  
(TRANSITIVE).

Best,

Alex.

[1] http://www.w3.org/TR/2009/REC-skos-reference-20090818/#L2413



>
> -- 
>
>
> Regards,
>
> Kingsley Idehen	      Weblog: http://www.openlinksw.com/blog/~kidehen
> President & CEO OpenLink Software     Web: http://www.openlinksw.com
>
>
>
>
>

--
Dr. Alexandre Passant
Digital Enterprise Research Institute
National University of Ireland, Galway
:me owl:sameAs <http://apassant.net/alex> .
Received on Thursday, 8 October 2009 15:28:35 UTC

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