>From 10000m heigth, a likely cause is an error in the prefix product: .
Anyway, unless you have a special reason to use XML , it's better to use Turtle format all the way. 2014-10-21 16:53 GMT+02:00 Bruno Baloi <[email protected]>: > 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, > Bruno > > > P.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 ? > > > -- Jean-Marc Vanel Déductions SARL - Consulting, services, training, Rule-based programming, Semantic Web http://deductions-software.com/ +33 (0)6 89 16 29 52 Twitter: @jmvanel , @jmvanel_fr ; chat: irc://irc.freenode.net#eulergui
