create RDF using defined OWL ontology

Question

I'm generating RDF for a database table(s). I generated OWL ontology for the table(s) using Protégé. I want to use this OWL ontology and create the RDF in RDF/XML format for table data using Jena. I know how to read and write RDF and OWL files into memory to generate Models, and I know how to use Resource, Property, ModelFactory, etc., classes to generate RDF. What I'm unable to do is use the ontology (OWL file) I generated and create the RDF instances for those OWL class(s). For example:

sample OWL:

<owl:Class rdf:about="Person"/>
<owl:Class rdf:about="Animal"/>

<owl:DatatypeProperty rdf:about="salary">
    <rdfs:domain rdf:resource="Person"/>
    <rdfs:range rdf:resource="&xsd;real"/>
</owl:DatatypeProperty>

desired RDF:

<Person rdf:about="Jack">
  <salary>1234</salary> 
</Person>

I'm able to generate RDF like this:

<rdf:Description rdf:about="Jack">
  <ns:salary>2004</ns:salary>
</rdf:Description>

Answer 1

What you want is a so called RDB2RDF mapper. Try D2RQ, a Java-based RDB2RDF mapper, for example.

Disclaimer: I'm co-chair of the W3C RDB2RDF Working Group and my group is heavily contributing to the development of D2RQ - there are a number of other implementations in various languages available as well.

Answer 2

The only difference between your desired output and the output that you are creating now is the presence of the triple :Jack rdf:type :Person (and, if you desire, defining the default namespace so that you don't need the ns: prefix on your XML elements).

Starting with your RDF

<rdf:Description rdf:about="Jack">
  <ns:salary>2004</ns:salary>
</rdf:Description>

and adding the triple Jack rdf:type Person, you would have

<rdf:Description rdf:about="Jack">
  <rdf:type rdf:resource="Person"/>
  <ns:salary>2004</ns:salary>
</rdf:Description>

The RDF/XML specification allows for a shorthand notation for rdf:type triples; if the URI for the type can be shorted to an XML name, then it can be used as the element name. Using this shorthand, you have

<ns:Person rdf:about="Jack">
  <ns:salary>2004</ns:salary>
</ns:Person>

which is your desired output, unless the prefix is really important. If it is, then you just need to use PrefixMapping#setNsPrefix to set a prefix. (Model implements PrefixMapping.)

model.setNsPrefix( "", "http://yourontologies.com/thisOntology#" );

and you'll get

<Person rdf:about="Jack">
  <salary>2004</salary>
</Person>

when you serialize the model.