CODEWITHSUNDEEP
sparqljenadbpedia
TheRadVillager
TheRadVillager

Reputation: 49

German DBpedia endpoint in HTTP Sparql Queries returns no result

I am using the Jena Java framework for querying DBpedia end point using SPARQL, to get the type for all points of interest in German cities. I am facing no issue for places that have English DBpedia entries. But, when it comes to place names to be queried from the German DBpedia endpoint (http://de.dbpedia.org/resource/Schloß_Nymphenburg), this query returns no result. This problem is also mentioned over here (http://mail-archives.apache.org/mod_mbox/jena-users/201110.mbox/%[email protected]%3E). Even after referring to this, I am unable to solve the problem. I don't know how to work with QueryEngineHTTP. I am adding two code snippets - one that works (first one - query for Allianz Arena : which has an English entry in DBpedia) and one that doesn't work (second one - for Schloß Nymphenburg, that has a German entry). This might be a very trivial issue, but I am unable to solve it. Any pointers to a solution would be very very helpful. Thanks a lot! Code 1 - working :

String service = "http://dbpedia.org/sparql";
final ParameterizedSparqlString query = new ParameterizedSparqlString(
            "PREFIX geo: <http://www.w3.org/2003/01/geo/wgs84_pos#>" +
            "PREFIX dbo: <http://dbpedia.org/ontology/>" +
            "PREFIX dcterms: <http://purl.org/dc/terms/>" +

            "SELECT * WHERE {" +
                "?s geo:lat ?lat ." +
                "?s geo:long ?long ." +
                "?s dcterms:subject ?sub}");
query.setIri("?s", "http://dbpedia.org/resource/Allianz_Arena");
QueryExecution qe = QueryExecutionFactory.sparqlService(service, query.toString());
ResultSet results = qe.execSelect();
ResultSetFormatter.out(System.out, results);

Code 2 - not working : 

String service = "http://dbpedia.org/sparql";
final ParameterizedSparqlString query = new ParameterizedSparqlString(
        "PREFIX geo: <http://www.w3.org/2003/01/geo/wgs84_pos#>" +
        "PREFIX dbo: <http://dbpedia.org/ontology/>" +
        "PREFIX dcterms: <http://purl.org/dc/terms/>" +

        "SELECT * WHERE {" +
            "?s geo:lat ?lat ." +
            "?s geo:long ?long ." +
            "?s dcterms:subject ?sub}");

query.setIri("?s", "http://de.dbpedia.org/resource/Schloß_Nymphenburg");
QueryExecution qe = QueryExecutionFactory.sparqlService(service, query.toString());
ResultSet results = qe.execSelect();
ResultSetFormatter.out(System.out, results);

Upvotes: 1

Views: 277

Answers (1)

user205512
user205512

Reputation: 8898

I don't think this is an issue with jena at all. Trying:

SELECT * WHERE {
    <http://de.dbpedia.org/resource/Schloß_Nymphenburg> ?p ?o }

at http://dbpedia.org/sparql I get no results: try it yourself.

SELECT * WHERE {
    <http://de.dbpedia.org/resource/Schloss_Nymphenburg> ?p ?o }

by contrast returns something, even if it's just a bunch of cross links.

Upvotes: 0

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