Oracle property path and arq property functions

Question

Hi,
I am using Oracle Jena Adapter. My problem is about property paths on Sparql queries. When I tried to query ”SELECT * WHERE { ?t rdf:type owl:ObjectProperty. ?t rdfs:domain ?o. ?o owl:unionOf ?union. ?union rdf:rest*/rdf:first ?member. }” from ModelOracleSem it gives me parser error.
But, if i try it using jena in-memory model, it works perfectly as below code.
hybridGraph = OracleGraphWrapperForOntModel.getInstance(graph1);
model = ModelFactory.createModelForGraph(hybridGraph);
ontModel = ModelFactory.createOntologyModel(OntModelSpec.OWL_MEM, model);
I also tried arq’s list function as “?union list:member ?member”. it does not return any results from ModelOracleSem. But when i try it from jena in-memory model, it works perfectly again.
Can anyone help me to solve this issue?
Thanks,
Regards,

Answer 1

Hi Mustafa,
We have generated the following code snippet to execute the SPARQL query using a ModelOracleSem model:
String szQuery = " PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> "+
             " PREFIX rdfs:  <http://www.w3.org/2000/01/rdf-schema#> " +
             " PREFIX owl:   <http://www.w3.org/2002/07/owl#> " +
            " select * where { " +
            " ?t rdf:type owl:ObjectProperty . " +
            " ?t rdfs:domain ?o . " +
            " ?o owl:unionOf ?union . " +
            " ?union rdf:rest*/rdf:first ?member ." +
    System.err.println("Create Oracle Connection");
    Oracle oracle = new Oracle(szJdbcURL, szUser, szPasswd);
    System.err.println("Create Oracle Model");
    ModelOracleSem oracleModel = ModelOracleSem.createOracleSemModel(
                                                            oracle, szModelName);
    oracleModel.removeAll();
    System.err.println("Populate model");
    String insertString = 
            " PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> "+
            " PREFIX rdfs:  <http://www.w3.org/2000/01/rdf-schema#> " +
            " PREFIX owl:   <http://www.w3.org/2002/07/owl#> " +
            " PREFIX urn:   <http://example/> " +
            " INSERT DATA "                                     +
            " { urn:objA rdf:type owl:ObjectProperty .                " +
            "   urn:objB rdf:type owl:ObjectProperty .                " +
            "   urn:objC rdf:type owl:ObjectProperty .                " +
            "   urn:objD rdf:type owl:ObjectProperty .                " +
            "   urn:objA rdfs:domain urn:dom1 .                " +
            "   urn:objB rdfs:domain urn:dom2 .                " +
            "   urn:objC rdfs:domain urn:dom3 .                " +
            "   urn:objD rdfs:domain urn:dom4 .                " +
            "   urn:dom1 owl:unionOf _:setA .                " +
            "   _:setA rdf:rest _:mem1 .                " +
            "   _:setA rdf:first urn:C1 .                " +
            "   _:mem1 rdf:first urn:C2 .                " +
            "   _:mem1 rdf:rest rdf:nil .                " +
    UpdateAction.parseExecute(insertString,  oracleModel);
    System.err.println("Population done " + oracleModel.size());
    System.err.println("Execute query over OracleModel");
    Query query = QueryFactory.create(szQuery, Syntax.syntaxARQ);
    QueryExecution qexec = QueryExecutionFactory.create(query, oracleModel);
    ResultSet results = qexec.execSelect();
    ResultSetFormatter.out(System.out, results, query);
Can you execute this code snippet and see if you get the expected result?
| t                     | o                     | union | member              |
===============================================================================
| <http://example/objA> | <http://example/dom1> | _:b0  | <http://example/C1> |
| <http://example/objA> | <http://example/dom1> | _:b0  | <http://example/C2> |
Thanks,
Gaby