I'm working with an ontology OWL and making a query about it.
My query is:
"PREFIX a: http://www.owl-ontologies.com/Indoor.owl# "
+ "SELECT ?X "
+ "WHERE { ?X a:hasDay a:" + day + " . "
+ " ?X a:hasRoom a:" + room + " . "
+ " ?X a:hasStartTime a:" + startTime +" }";
At the moment to make the query, the console of NetBeans throw me:
Undefined object property used in query: http://www.owl-ontologies.com/Indoor.owl#hasStartTime
But hasStartTime in the ontology isn't an object property, it is a data type (int).
Assuming that the value of the Java variable startTime is e.g. 420 (7am), if you look at your SPARQL query, the last triple pattern is made by
?X a:hasStartTime a: plus value of ``startTime,
i.e. it results in
?X a:hasStartTime a:420
RDF literals have to be put in quotes without a prefix - it's a literal and not a prefixed URI, e.g.
?X a:hasStartTime 420
or to make the datatype more explicit (for integer values the above is just a shortcut)
?X a:hasStartTime "420"^^<http://www.w3.org/2001/XMLSchema#integer>
