Re: Missing results on DBPedia end point

  Hi Patrick,

>> 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/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.
>
> We will investigate this and report back to the list.

Thanks for checking this. Just to let you know, I followed Richard 
intuition and tried this, which indeed works:
SELECT ?result WHERE { ?result 
<http://dbpedia.org/ontology/formationDate> ?date. FILTER(str(?date) = 
"2006-09-13") }


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 Monday, 27 September 2010 10:55:37 UTC