SPARQL query on Protege for Number of Classes

Question

In order to determine the number of classes in a .owl file,

I was advised to use the following SPARQL query:

SELECT ( count(?class) as ?count )
    WHERE { graph <put_your_model_graph_name_here> { ?class a owl:Class . } }

However, when I replace the put_your_model_graph_name_here with my ontology IRI, I get 0

I also tried http://blahblahblah followed immediately by # to no avail.

What am I doing wrong?

Answer 1

Difficult to tell without seeing how you are loading and querying the data. Try using:

SELECT ( count(?class) as ?count ) { ?class a owl:Class }

which will query the default graph, or

SELECT ?g ( count(?class) as ?count ) 
{ graph ?g { ?class a owl:Class } }
group by ?g

which will give counts for all the named graphs.