SPARQL query using rdf:ID returns no results

Question

I have an owl file and I am trying to run queries on it but not getting any results please some one help me to figure it out and explain basic querying

public static void main(String[] args) {
      String filename="H:/Samson_study/nodeTest/hRESTS-TC3/ontology/ApothecaryOntology.owl";
      Model model=ModelFactory.createDefaultModel();
      OntModel model1=ModelFactory.createOntologyModel(OntModelSpec.OWL_DL_MEM,model);

      try
      {          File file=new File(filename);
          FileInputStream reader=new FileInputStream(file);
          model.read(reader,null);


          String query1=" PREFIX rdfs:  PREFIX rdf:  PREFIX my:  SELECT  ?result WHERE { ?result rdf:ID my:HealthInsuranceNumber .}";

          Query query=QueryFactory.create(query1);
          QueryExecution exe=QueryExecutionFactory.create(query, model1);
          ResultSet RES=exe.execSelect();
          ResultSetFormatter.out(System.out, RES, query);
      }catch(Exception e)
      {
          e.printStackTrace();
      }
  }

The ontology is as follows:

I am not getting error but I dont know how to query owl file please help

Joshua Taylor · Accepted Answer

Your query, with newlines added for readability, is:

PREFIX rdfs: 
PREFIX rdf: 
PREFIX my: 

SELECT  ?result WHERE {
  ?result rdf:ID my:HealthInsuranceNumber .
}

While you see rdf:ID in your RDF/XML file, it's not actually a property in the RDF triples; instead, it's used to indicate what the IRI of a resource in the RDF graph is. For instance, the snippet:

encode the RDF triple:

...#Costs rdf:type owl:Class

where the ... is the base IRI of your ontology. This is described in section 2.14 Abbreviating URIs: rdf:ID and xml:base of the RDF/XML specification. That specification is kind of long and complicated, like RDF/XML. RDF/XML is just a serialization format for RDF, though. RDF itself is pretty simple. Whenever possible, I'd advise that you don't look directly at the RDF/XML serialization of an RDF graph. Instead, try saving as Turtle. It's much more human readable, and you'll have a much better idea of what triples are actually in the graph. E.g., your ontology in Turtle looks like this (I haven't copied the whole thing):

@prefix :       .
@prefix rdf:    .
@prefix owl:    .
@prefix rdfs:   .

:Person  a      owl:Class .

:Patient  a              owl:Class ;
        rdfs:subClassOf  :Person .

:HospitalPhysician  a    owl:Class ;
        rdfs:subClassOf  :Physician .

:TelephoneNumber  a       owl:Class ;
        rdfs:subClassOf   :Number ;
        owl:disjointWith  :HealthInsuranceNumber .

:Physician_hasID  a  owl:FunctionalProperty , owl:InverseFunctionalProperty , owl:ObjectProperty ;
        rdfs:domain  :Physician ;
        rdfs:range   :PhysicianID .

:Disease_hasSymptom  a  owl:FunctionalProperty , owl:ObjectProperty ;
        rdfs:domain  :Disease ;
        rdfs:range   :Symptom .

That's almost identical to the corresponding SPARQL syntax.

SPARQL query using rdf:ID returns no results

Answers (2)

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