Hi,
for research purposes I have imported DBpedia dumps into a local Virtuoso
06.00.3123 instance using the following command:
ttlp_mt (file_to_string_output ('$f'), '', '$g', 255);
I am using the 255 flag cause I need all triples in the store, also the
erroneous ones.
Now, when executing the following query against the local SPARQL endpoint...
select ?x where {?x ?y ?z} LIMIT 5
...everything is fine. I get the following result (in RDF/XML)
<rdf:RDF xmlns:res="http://www.w3.org/2005/sparql-results#";
xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#";>
<rdf:Description rdf:nodeID="rset">
<rdf:type rdf:resource="http://www.w3.org/2005/sparql-results#ResultSet"; />
<res:resultVariable>x</res:resultVariable>
<res:solution rdf:nodeID="r0">
<res:binding rdf:nodeID="r0c0"><res:variable>x</res:variable><res:value
rdf:resource="http://dbpedia33.mminf.univie.ac.at/resource/%22S%22_Bridge_II"/></res:binding>
</res:solution>
...
</rdf:Description>
</rdf:RDF>
...but if execute the same query using DISTINCT I get the following result
<rdf:RDF xmlns:res="http://www.w3.org/2005/sparql-results#";
xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#";>
<rdf:Description rdf:nodeID="rset">
<rdf:type rdf:resource="http://www.w3.org/2005/sparql-results#ResultSet"; />
<res:resultVariable>x</res:resultVariable>
<res:solution rdf:nodeID="r0">
<res:binding
rdf:nodeID="r0c0"><res:variable>x</res:variable><res:value>http://dbpedia33.mminf.univie.ac.at/resource/%22S%22_Bridge_II</res:value></res:binding>
</res:solution>
...
</rdf:Description>
</rdf:RDF>
so the binding for ?x is interpreted as a literal and not a resource. When
using client APIs such as Jena, the results are then converted into Literal
objects which causes some troubles in the application I am currently working on.
Did I miss anything or is this a known issue? Is there a way to fix that?
Thanks a lot,
Bernhard
______________________________________________________
Research Group Multimedia Information Systems
Department of Distributed and Multimedia Systems
Faculty of Computer Science
University of Vienna
Postal Address: Liebiggasse 4/3-4, 1010 Vienna, Austria
Phone: +43 1 42 77 39635 Fax: +43 1 4277 39649
E-Mail: [email protected]
WWW: http://www.cs.univie.ac.at/bernhard.haslhofer
