Hi,
I am new to Jena, but, I have successfully installed SDB in MySQL and load RDF
data into the RDF store. Recently, I try to set up the SPARQL query engine by
trying the examples in the SDB-1.3.4/src-examples first. I am quite sure that I
have successfully connected to the database, but, the problem happens in the
code of ResultsSet rs= qe.execSelect():
String queryString = "SELECT DISTINCT ?s { ?s ?p ?o }";
Query query = QueryFactory.create(queryString) ;
SDBConnection conn = new SDBConnection(jdbcConnection) ;
Store store = StoreFactory.create(storeDesc, conn) ;
// Model model = SDBFactory.connectDefaultModel(store) ;
Dataset ds = SDBFactory.connectDataset(conn, storeDesc);
QueryExecution qe = QueryExecutionFactory.create(query, ds) ;
try {
ResultSet rs = qe.execSelect() ;
ResultSetFormatter.out(rs) ;
}
finally {
qe.close() ;
}
1st, if I use DatasetStore to trigger the SDB query engine, like:
Dataset ds = SDBFactory.connectDataset(conn, storeDesc);
QueryExecution qe = QueryExecutionFactory.create(query, ds)
;
The code ResultSet rs=qe.execSelect() will failed and qe.close() will be
executed. (I attach the error information with this email.
2nd, if I use
Model model = SDBFactory.connectDefaultModel(store);
QueryExecution qe = QueryExecutionFactory.create(query, ds);
The code ResultSet rs=qe.execSelect() won't have error, but the returned
results seems just empty.
I would appreciate if you know where is the problem.
Thanks,
Liqin
Exception in thread "main" java.lang.NoSuchMethodError:
com.hp.hpl.jena.sparql.core.Quad.isDefaultGraphIRI()Z
at
com.hp.hpl.jena.sdb.compiler.SqlStageBasicQuad.build(SqlStageBasicQuad.java:67)
at com.hp.hpl.jena.sdb.compiler.SqlStageList.build(SqlStageList.java:23)
at
com.hp.hpl.jena.sdb.compiler.QuadBlockCompilerMain.compile(QuadBlockCompilerMain.java:62)
at
com.hp.hpl.jena.sdb.compiler.TransformSDB.transform(TransformSDB.java:68)
at
com.hp.hpl.jena.sparql.algebra.op.OpQuadPattern.apply(OpQuadPattern.java:84)
at
com.hp.hpl.jena.sparql.algebra.Transformer$ApplyTransformVisitor.visit0(Transformer.java:261)
at
com.hp.hpl.jena.sparql.algebra.OpVisitorByType.visit(OpVisitorByType.java:32)
at
com.hp.hpl.jena.sparql.algebra.op.OpQuadPattern.visit(OpQuadPattern.java:85)
at
com.hp.hpl.jena.sparql.algebra.OpWalker$WalkerVisitor.visit0(OpWalker.java:76)
at
com.hp.hpl.jena.sparql.algebra.OpVisitorByType.visit(OpVisitorByType.java:32)
at
com.hp.hpl.jena.sparql.algebra.op.OpQuadPattern.visit(OpQuadPattern.java:85)
at
com.hp.hpl.jena.sparql.algebra.OpWalker$WalkerVisitor.visit1(OpWalker.java:84)
at
com.hp.hpl.jena.sparql.algebra.OpVisitorByType.visitModifer(OpVisitorByType.java:26)
at
com.hp.hpl.jena.sparql.algebra.OpVisitorByType.visit(OpVisitorByType.java:107)
at com.hp.hpl.jena.sparql.algebra.op.OpProject.visit(OpProject.java:34)
at
com.hp.hpl.jena.sparql.algebra.OpWalker$WalkerVisitor.visit1(OpWalker.java:84)
at
com.hp.hpl.jena.sparql.algebra.OpVisitorByType.visitModifer(OpVisitorByType.java:26)
at
com.hp.hpl.jena.sparql.algebra.OpVisitorByType.visit(OpVisitorByType.java:113)
at com.hp.hpl.jena.sparql.algebra.op.OpDistinct.visit(OpDistinct.java:34)
at com.hp.hpl.jena.sparql.algebra.OpWalker.walk(OpWalker.java:40)
at com.hp.hpl.jena.sparql.algebra.OpWalker.walk(OpWalker.java:30)
at
com.hp.hpl.jena.sparql.algebra.Transformer.applyTransformation(Transformer.java:99)
at
com.hp.hpl.jena.sparql.algebra.Transformer.transformation(Transformer.java:92)
at
com.hp.hpl.jena.sparql.algebra.Transformer.transformation(Transformer.java:81)
at
com.hp.hpl.jena.sparql.algebra.Transformer.transform(Transformer.java:42)
at
com.hp.hpl.jena.sdb.compiler.QueryCompilerMain.compile(QueryCompilerMain.java:58)
at com.hp.hpl.jena.sdb.compiler.SDBCompile.compile(SDBCompile.java:75)
at com.hp.hpl.jena.sdb.engine.QueryEngineSDB.init(QueryEngineSDB.java:88)
at
com.hp.hpl.jena.sdb.engine.QueryEngineSDB.<init>(QueryEngineSDB.java:55)
at
com.hp.hpl.jena.sdb.engine.QueryEngineSDB$QueryEngineFactorySDB.create(QueryEngineSDB.java:153)
at
com.hp.hpl.jena.sparql.engine.QueryExecutionBase.getPlan(QueryExecutionBase.java:426)
at
com.hp.hpl.jena.sparql.engine.QueryExecutionBase.startQueryIterator(QueryExecutionBase.java:400)
at
com.hp.hpl.jena.sparql.engine.QueryExecutionBase.execResultSet(QueryExecutionBase.java:408)
at
com.hp.hpl.jena.sparql.engine.QueryExecutionBase.execSelect(QueryExecutionBase.java:135)
at dev.skass.query.QueryFromStore.query(QueryFromStore.java:71)
at dev.skass.query.QueryFromStore.main(QueryFromStore.java:50)
