Missing results on DBPedia end point

  Hello,

There seems to be an issue with the SPARQL end point of DBPedia, 
http://dbpedia.org/sparql.

When I run this first query:

    SELECT ?result WHERE {<http://dbpedia.org/resource/WVNS-DT2
    <http://dbpedia.org/resource/WVNS-DT2>>
    <http://dbpedia.org/ontology/formationDate
    <http://dbpedia.org/ontology/formationDate>>  ?result. }

I get the following result telling me that ?result is a date:

    <sparql xmlns="http://www.w3.org/2005/sparql-results#"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://www.w3.org/2001/sw/DataAccess/rf1/result2.xsd">
    <head>
    <variable name="result"/>
    </head>
    <results distinct="false" ordered="true">
    <result>
    <binding name="result"><literal
    datatype="http://www.w3.org/2001/XMLSchema#date">2006-09-13</literal></binding>
    </result>
    </results>
    </sparql>


But when I want to find a resource which matches that specific date, no 
result are returned:

    SELECT ?result WHERE { ?result
    <http://dbpedia.org/ontology/formationDate> 
    "2006-09-13"^^<http://www.w3.org/2001/XMLSchema#date>. }

gives

    <sparql xmlns="http://www.w3.org/2005/sparql-results#"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://www.w3.org/2001/sw/DataAccess/rf1/result2.xsd">
    <head>
    <variable name="result"/>
    </head>
    <results distinct="false" ordered="true">
    </results>
    </sparql>


Could this be a bug of some sort? I also tried to run the same couple of 
queries on http://lod.openlinksw.com/sparql and everything works fine there.


Cheers,
Christophe


-- 
Dr. Christophe Guéret (cgueret@few.vu.nl)
http://cgueret.net
Postdoc working on SOKS (http://www.few.vu.nl/soks)
Knowledge Representation&  Reasoning Group
Computational Intelligence Group
Department of Computer Science, AI
VU University Amsterdam

Received on Sunday, 26 September 2010 15:03:48 UTC