CODEWITHSUNDEEP
sparqljenadbpedia
blueomega
blueomega

Reputation: 381

Jena Sparql and construct

CONSTRUCT is an alternative SPARQL result clause to SELECT. Instead of returning a table of result values, CONSTRUCT returns an RDF graph. For instance, running this query in the following Java code produces an HttpException: 406 Unacceptable. But if instead of the CONSTRUCT block, I choose SELECT ?x, it's just fine. Does Jena support CONSTRUCT, and if so, how? Both queries are acceptable to the DBpedia endpoint.

PREFIX : <http://dbpedia.org/resource/>
PREFIX onto: <http://dbpedia.org/ontology/>

CONSTRUCT { 
    :France onto:anthem ?x
}

WHERE
{
  :France onto:anthem ?x .
}

Query query = QueryFactory.create("the query goes here");
QueryExecution qexec = QueryExecutionFactory.sparqlService("http://dbpedia.org/sparql",     query);
ResultSet results = qexec.execSelect();  
ResultSetFormatter.out(System.out, results, query);

Upvotes: 4

Views: 5489

Answers (2)

Abhaya
Abhaya

Reputation: 2136

ResultSetFormatter.out(System.out, results, query) cannot find symbol and identifier expected error occurs at this point

Upvotes: 2

cygri
cygri

Reputation: 9472

Jena supports CONSTRUCT, but to get the result you need to call a different method, because execSelect and ResultSet are only for SELECT queries. Use this instead:

Model results = qexec.execConstruct();
results.write(System.out, "TURTLE");

Model is Jena's interface for accessing RDF graphs, see the javadocs for details.

Upvotes: 11

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