Hello, I am new to Jena, and to the semantic space as well.
I am trying to build an application using Jena and I am encountering some issues.
I built the Ontology using the Ontology APIs. It all looks good, and I can use a reasoner to get information out. I then generate the XML doc representing the Ontology. I can also use Protege to visualize the ontology.
So far so good.The problem comes when I try to use SPARQL. When i use the query " ?subject rdfs:subClassOf ?object " it works fine. However if i try to use something to the effect of: "?subject rdfs:subclassOf product:Food" I get nothing (I am trying to get all the classes that are subclasses of Food), and there are many subclasses of Food declared. I have attached the generated XML Ontology.
If however I use OWL-DL (DL-Query in Protege) or in code, it works fine i.e. I get the necessary subclasses.
So my question is what am I doing wrong ? Is the way the graph is stored in XML causing the problem for SPARQL, or am I misunderstanding the way to use the SPARQL query ?
Any insight or guidance would be greatly appreciated regards, BrunoP.S. I had a look at the Wine ontology that is publicly available, and I noticed that in the XML doc, that Sub Classes are referred to by "resource" , whereas in the "Product" graph that I generate, they are referred to by "ID". Could that be a problem ? And if it is what do I need to use in the APIs to rectify this ?
engage.product.owl.rdf
Description: application/rdf
