- From: Christophe Guéret <cgueret@few.vu.nl>
- Date: Mon, 27 Sep 2010 12:54:55 +0200
- To: Patrick van Kleef <pkleef@openlinksw.com>
- CC: Linked Data community <public-lod@w3.org>, dbpedia-discussion@lists.sourceforge.net
- Message-ID: <4CA077FF.5070904@few.vu.nl>
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