RDF Schema/OWL types lacking


(Pete Rivett) #1

I’m probably missing something basic, but it seems that the RDF Schema types seem to be lacking. Do I need to explicitly load the RDFS ontology?
For example i
select * where {<http://www.w3.org/2000/01/rdf-schema#subClassOf> ?p ?o}
Gives nothing. Even with reasoning on it gives only:
rdf:type owl:Thing.

Surely, even without reasoning, it should give:
rdf:type rdf:Property
as per https://www.w3.org/TR/rdf-schema/#ch_subclassof

The same goes for the OWL classes e.g. select * where {owl:Class ?p ?o}
Do I need to explicitly load an ontology for OWL itself?


(zachary.whitley) #2

It’s funny that I’ve been using reasoning but never really thought about it but just took it for granted that it was there. What I’m guessing is that it’s sort of there but it’s not. Let me elaborate. When Stardog starts up it looks at your database and extracts the ontology. I’m guessing that rdfs and owl are included by default in the extracted ontology. So it’s there for the reasoner but it’s not in the database for you to query. If you need to actually query the triples that are a part of rdfs or owl I believe that you would need to explicitly add them to your database.