I'm trying to get Individuals in my Ontology which have a certain property. I want all Individuals which are linked to a foot by the hasFoot property. In the past I used Jena's iterators, but now i want to use SPARQL. The Java code that creates my query:
String queryString =
"PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>"+
"PREFIX owl: <http://www.w3.org/2002/07/owl#>" +
"PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>" +
"PREFIX test: <file:/test#>"+
"select ?uri"+
"where { "+
"?uri test:hasFoot ?foot"+
"} \n ";
But I don't get any results with this query. When I query for the properties of all triples I get these results:
"select ?prop "+
"where { "+
"?uri ?prop ?subj"+
"} \n ";
<file:/test#hasFoot>
<file:/test#hasFoot>
<file:/test#hasFoot>
<file:/test#hasFoot>
<file:/test#hasAge>
<file:/test#hasName>
So SPARQL queries are clearly working. I can even search for the rdf:types, so the rdf namespace works, only my namespace (test) doesnt seem to work. I have also tried to write out the whole property name ("file:/test#hasFoot") with no results. Does anyone have an idea what I am missing?
Here is my ontology:
<rdf:RDF
xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
xmlns:test="file:/test#"
xmlns:owl="http://www.w3.org/2002/07/owl#"
xmlns:xsd="http://www.w3.org/2001/XMLSchema#"
xmlns:rdfs="http://www.w3.org/2000/01/rdf-schema#" >
<rdf:Description rdf:about="file:/test#Foot2">
<rdf:type rdf:resource="file:/test#Foot"/>
<rdf:type rdf:resource="http://www.w3.org/2002/07/owl#NamedIndividual"/>
</rdf:Description>
<rdf:Description rdf:about="file:/test#Peter">
<test:hasHand rdf:resource="file:/test#Hand2"/>
<test:hasHand rdf:resource="file:/test#Hand1"/>
<test:hasFoot rdf:resource="file:/test#Foot6"/>
<test:hasFoot rdf:resource="file:/test#Foot5"/>
<test:hasName>Peter</test:hasName>
<test:hasAge>98</test:hasAge>
<rdf:type rdf:resource="file:/test#Individuum"/>
<rdf:type rdf:resource="http://www.w3.org/2002/07/owl#NamedIndividual"/>
</rdf:Description>
<rdf:Description rdf:about="file:/test#hasName">
<rdf:type rdf:resource="http://www.w3.org/2002/07/owl#DatatypeProperty"/>
</rdf:Description>
<rdf:Description rdf:about="file:/test#Foot1">
<rdf:type rdf:resource="file:/test#Foot"/>
<rdf:type rdf:resource="http://www.w3.org/2002/07/owl#NamedIndividual"/>
</rdf:Description>
<rdf:Description rdf:about="file:/test#Foot3">
<rdf:type rdf:resource="file:/test#Foot"/>
<rdf:type rdf:resource="http://www.w3.org/2002/07/owl#NamedIndividual"/>
</rdf:Description>
<rdf:Description rdf:about="file:/test#Hand">
<rdf:type rdf:resource="http://www.w3.org/2002/07/owl#Class"/>
</rdf:Description>
<rdf:Description rdf:about="file:/test#hasAge">
<rdf:type rdf:resource="http://www.w3.org/2002/07/owl#DatatypeProperty"/>
</rdf:Description>
<rdf:Description rdf:about="file:/test#Human">
<rdf:type rdf:resource="http://www.w3.org/2002/07/owl#Class"/>
</rdf:Description>
<rdf:Description rdf:about="file:/test#hasFoot">
<rdf:type rdf:resource="http://www.w3.org/2002/07/owl#ObjectProperty"/>
</rdf:Description>
<rdf:Description rdf:about="file:/test#Doggy">
<test:hasFoot rdf:resource="file:/test#Foot4"/>
<test:hasFoot rdf:resource="file:/test#Foot3"/>
<test:hasFoot rdf:resource="file:/test#Foot2"/>
<test:hasFoot rdf:resource="file:/test#Foot1"/>
<test:hasAge>7</test:hasAge>
<test:hasName>Doggy</test:hasName>
<rdf:type rdf:resource="file:/test#Individuum"/>
<rdf:type rdf:resource="http://www.w3.org/2002/07/owl#NamedIndividual"/>
</rdf:Description>
<rdf:Description rdf:about="file:/test#Hand2">
<rdf:type rdf:resource="file:/test#Hand"/>
<rdf:type rdf:resource="http://www.w3.org/2002/07/owl#NamedIndividual"/>
</rdf:Description>
<rdf:Description rdf:about="file:/test#Foot6">
<rdf:type rdf:resource="file:/test#Foot"/>
<rdf:type rdf:resource="http://www.w3.org/2002/07/owl#NamedIndividual"/>
</rdf:Description>
<rdf:Description rdf:about="file:/test#hasHand">
<rdf:type rdf:resource="http://www.w3.org/2002/07/owl#ObjectProperty"/>
</rdf:Description>
<rdf:Description rdf:about="file:/test#Individuum">
<rdf:type rdf:resource="http://www.w3.org/2002/07/owl#Class"/>
</rdf:Description>
<rdf:Description rdf:about="file:/test#Foot">
<rdf:type rdf:resource="http://www.w3.org/2002/07/owl#Class"/>
</rdf:Description>
<rdf:Description rdf:about="file:/test">
<rdf:type rdf:resource="http://www.w3.org/2002/07/owl#Ontology"/>
</rdf:Description>
<rdf:Description rdf:about="file:/test#Foot5">
<rdf:type rdf:resource="file:/test#Foot"/>
<rdf:type rdf:resource="http://www.w3.org/2002/07/owl#NamedIndividual"/>
</rdf:Description>
<rdf:Description rdf:about="file:/test#Hand1">
<rdf:type rdf:resource="file:/test#Hand"/>
<rdf:type rdf:resource="http://www.w3.org/2002/07/owl#NamedIndividual"/>
</rdf:Description>
<rdf:Description rdf:about="file:/test#Foot4">
<rdf:type rdf:resource="file:/test#Foot"/>
<rdf:type rdf:resource="http://www.w3.org/2002/07/owl#NamedIndividual"/>
</rdf:Description>
</rdf:RDF>
Your custom scheme is missing an authority and isn't a valid IRI.
You can test the IRIs that your using by using one of the IRIFactory types that exist in jena. For example, if I were to run one of your IRIs through:
@Test
public void correctUri() {
final IRIFactory factory = IRIFactory.iriImplementation();
final IRI iri = factory.construct("file:/test#johnsFoot");
}
I get the following exception, indicating that the authority portion of the IRI is missing, so it's not an IRI:
org.apache.jena.iri.impl.IRIImplException: <file:/test#johnsFoot> Code: 57/REQUIRED_COMPONENT_MISSING in AUTHORITY: A component that is required by the scheme is missing.
at org.apache.jena.iri.impl.AbsIRIFactoryImpl.throwAnyErrors(AbsIRIFactoryImpl.java:65)
at org.apache.jena.iri.impl.AbsIRIFactoryImpl.construct(AbsIRIFactoryImpl.java:48)
at SO_Test.correctUri(SO_Test.java:87)
Updating your ontology to use file://test# rather than file:/test# and running the following query:
@Test
public void getAllProperties2() {
final Query query = QueryFactory.create(
"PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>"+
"PREFIX owl: <http://www.w3.org/2002/07/owl#>" +
"PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>" +
"PREFIX test: <file://test#>"+
"select * "+
"where { "+
"?uri ?prop ?subj"+
"} \n "
);
final QueryExecution exec = QueryExecutionFactory.create(query, model1);
final ResultSetRewindable results = ResultSetFactory.copyResults(exec.execSelect());
exec.close();
ResultSetFormatter.out(System.out, results, query);
results.reset();
}
Results in the output that you expect. Most notable is that the prefixes that you want to see are associated with your elements. The output is as follows:
---------------------------------------------------------
| uri | prop | subj |
=========================================================
| test:Hand | rdf:type | owl:Class |
| test:Foot3 | rdf:type | owl:NamedIndividual |
| test:Foot3 | rdf:type | test:Foot |
| test:Human | rdf:type | owl:Class |
| <file://test> | rdf:type | owl:Ontology |
| test:Hand2 | rdf:type | owl:NamedIndividual |
| test:Hand2 | rdf:type | test:Hand |
| test:Individuum | rdf:type | owl:Class |
| test:hasName | rdf:type | owl:DatatypeProperty |
| test:Foot2 | rdf:type | owl:NamedIndividual |
| test:Foot2 | rdf:type | test:Foot |
| test:Hand1 | rdf:type | owl:NamedIndividual |
| test:Hand1 | rdf:type | test:Hand |
| test:Foot1 | rdf:type | owl:NamedIndividual |
| test:Foot1 | rdf:type | test:Foot |
| test:hasAge | rdf:type | owl:DatatypeProperty |
| test:hasFoot | rdf:type | owl:ObjectProperty |
| test:hasHand | rdf:type | owl:ObjectProperty |
| test:Peter | rdf:type | owl:NamedIndividual |
| test:Peter | rdf:type | test:Individuum |
| test:Peter | test:hasAge | "98" |
| test:Peter | test:hasName | "Peter" |
| test:Peter | test:hasFoot | test:Foot5 |
| test:Peter | test:hasFoot | test:Foot6 |
| test:Peter | test:hasHand | test:Hand1 |
| test:Peter | test:hasHand | test:Hand2 |
| test:Foot6 | rdf:type | owl:NamedIndividual |
| test:Foot6 | rdf:type | test:Foot |
| test:Foot5 | rdf:type | owl:NamedIndividual |
| test:Foot5 | rdf:type | test:Foot |
| test:Doggy | rdf:type | owl:NamedIndividual |
| test:Doggy | rdf:type | test:Individuum |
| test:Doggy | test:hasName | "Doggy" |
| test:Doggy | test:hasAge | "7" |
| test:Doggy | test:hasFoot | test:Foot1 |
| test:Doggy | test:hasFoot | test:Foot2 |
| test:Doggy | test:hasFoot | test:Foot3 |
| test:Doggy | test:hasFoot | test:Foot4 |
| test:Foot4 | rdf:type | owl:NamedIndividual |
| test:Foot4 | rdf:type | test:Foot |
| test:Foot | rdf:type | owl:Class |
---------------------------------------------------------
With your previous data, the following query results in different results:
@Test
public void getAllProperties() {
final Query query = QueryFactory.create(
"PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>"+
"PREFIX owl: <http://www.w3.org/2002/07/owl#>" +
"PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>" +
"PREFIX test: <file:/test#>"+
"select * "+
"where { "+
"?uri ?prop ?subj"+
"} \n "
);
final QueryExecution exec = QueryExecutionFactory.create(query, model0);
final ResultSetRewindable results = ResultSetFactory.copyResults(exec.execSelect());
exec.close();
ResultSetFormatter.out(System.out, results, query);
results.reset();
}
results in:
----------------------------------------------------------------------------
| uri | prop | subj |
============================================================================
| <file:/test#Hand> | rdf:type | owl:Class |
| <file:/test#Foot1> | rdf:type | owl:NamedIndividual |
| <file:/test#Foot1> | rdf:type | <file:/test#Foot> |
| <file:/test#hasFoot> | rdf:type | owl:ObjectProperty |
| <file:/test#Doggy> | rdf:type | owl:NamedIndividual |
| <file:/test#Doggy> | rdf:type | <file:/test#Individuum> |
| <file:/test#Doggy> | <file:/test#hasName> | "Doggy" |
| <file:/test#Doggy> | <file:/test#hasAge> | "7" |
| <file:/test#Doggy> | <file:/test#hasFoot> | <file:/test#Foot1> |
| <file:/test#Doggy> | <file:/test#hasFoot> | <file:/test#Foot2> |
| <file:/test#Doggy> | <file:/test#hasFoot> | <file:/test#Foot3> |
| <file:/test#Doggy> | <file:/test#hasFoot> | <file:/test#Foot4> |
| <file:/test#Foot6> | rdf:type | owl:NamedIndividual |
| <file:/test#Foot6> | rdf:type | <file:/test#Foot> |
| <file:/test#hasHand> | rdf:type | owl:ObjectProperty |
| <file:/test#hasName> | rdf:type | owl:DatatypeProperty |
| <file:/test> | rdf:type | owl:Ontology |
| <file:/test#Foot5> | rdf:type | owl:NamedIndividual |
| <file:/test#Foot5> | rdf:type | <file:/test#Foot> |
| <file:/test#Human> | rdf:type | owl:Class |
| <file:/test#Hand2> | rdf:type | owl:NamedIndividual |
| <file:/test#Hand2> | rdf:type | <file:/test#Hand> |
| <file:/test#Foot4> | rdf:type | owl:NamedIndividual |
| <file:/test#Foot4> | rdf:type | <file:/test#Foot> |
| <file:/test#hasAge> | rdf:type | owl:DatatypeProperty |
| <file:/test#Hand1> | rdf:type | owl:NamedIndividual |
| <file:/test#Hand1> | rdf:type | <file:/test#Hand> |
| <file:/test#Foot3> | rdf:type | owl:NamedIndividual |
| <file:/test#Foot3> | rdf:type | <file:/test#Foot> |
| <file:/test#Peter> | rdf:type | owl:NamedIndividual |
| <file:/test#Peter> | rdf:type | <file:/test#Individuum> |
| <file:/test#Peter> | <file:/test#hasAge> | "98" |
| <file:/test#Peter> | <file:/test#hasName> | "Peter" |
| <file:/test#Peter> | <file:/test#hasFoot> | <file:/test#Foot5> |
| <file:/test#Peter> | <file:/test#hasFoot> | <file:/test#Foot6> |
| <file:/test#Peter> | <file:/test#hasHand> | <file:/test#Hand1> |
| <file:/test#Peter> | <file:/test#hasHand> | <file:/test#Hand2> |
| <file:/test#Foot2> | rdf:type | owl:NamedIndividual |
| <file:/test#Foot2> | rdf:type | <file:/test#Foot> |
| <file:/test#Foot> | rdf:type | owl:Class |
| <file:/test#Individuum> | rdf:type | owl:Class |
----------------------------------------------------------------------------
It seems that jena does not make a best-guess effort at enforcing the qname/prefix standards on invalid IRIs.