2 Replies Latest reply on Jul 13, 2010 5:18 AM by 784044

    How to apply ontology on the existing RDF model

    784044
      Hi,
      I am new to Semantic web technologies.I am facing following issue.
      I have installed Oracle 11g with semantic support.
      I have few tables which stores customer,products information. eg :CUSTOMER_MASTER,PRODUCT_MASTER.
      Now used d2rq client and generated N-TRIPLE files by connecting to the above scheme i.e converted the tuples to triples generated RDF content.
      I could store the RDF data into Oracle 11g using the jena APIs. I was successfull till this point.

      Now , I have defined an ontology for the above entities using protege. I was able to store the model to Oracle 11g using Jena APIs.
      But I am confused with following issues.
      1. How can I apply my ontology definition to my existing RDF model.
      i.e. - I have created a ontology definition MyOntology.owl and loaded into Oracle 11g name MyOntologyModel.
      I already have another RDF model which got generated from the relational table i.e. CustomerRDFModel .
      Now, how can I apply MyOntologyModel to CustomerRDFModel and execute meaningfull queries.

      While defining the ontology, shall I use the same class names which are used in the CustomerRDFModel ? How can I link my ontology and RDF content ?
      eg:- I have a entities such as CUSTOMER_MASTER and PRODUCT_MASTER .Now in my ontology, if I need to bring some ontology definitions , shall I use the same entity names while defining Ontology.
      Otherwise, how we can apply ontology on existing relational tables ?
      Is it not required to convert the tuples(relational data) to RDF data for running the semantic queries ?

      Please provide me some pointers on these issues .
      Thanks
      Aneesh K
        • 1. Re: How to apply ontology on the existing RDF model
          617912
          Let me explain it like this:

          The triples (data) you automatically generated using D2RQ must conform to some ontology definition (lets use ontology schema in place of ontology definition for easier understanding). I believe D2RQ generates ontology schema/definition also, along with data. Please check once. But if it does not then it is your responsibility to either manually/automatically generate a ontology definition/schema that has the same class & property names (URIs) as what your data (generated thru D2RQ) has.

          Once you have a ontology schema and ontology data (that conforms to our schema), you have two options to link them:

          1) Load both schema and data to a single ontology model in oracle database.
          2) Load them into separate models and while querying you can mention both the models in the query.

          But I believe that the database does not do any kind of validation of data against schema in any of the above case (probably because that is what is intended in the W3C OWL specification - no distinction btwn data & schema) . But if you have schema in the database you can actually do a lot if inferencing (RDFS inferencing, OWL inferencing etc..)

          Thanks,
          Rajesh.

          PS: All those Ontology pundits, correct me if I am wrong.

          Edited by: rajesh narni on Jul 9, 2010 4:30 AM
          • 2. Re: How to apply ontology on the existing RDF model
            784044
            Hi Rajesh,
            Thanks for your quick response.
            I am trying the options which you have suggested.

            Thanks
            Aneesh K