Here is a sample code of the above stated problem.
public class ReadTDB {
public static void main(String[] args){
// open TDB dataset
String directory = "./MyDatabases/OntologyTDB"; // My TDB created
beforehand
Dataset dataset = TDBFactory.createDataset(directory);
//Read Model from the tdb
Model tdb = dataset.getDefaultModel();
// read the OntModel from the Model
OntModel m = ModelFactory.createOntologyModel( OntModelSpec.OWL_MEM,
tdb );
String sparqlQueryString=null;
sparqlQueryString = "SELECT ?s WHERE { ?s <
http://www.w3.org/2000/01/rdf-schema#subClassOf> <
http://www.owl-ontologies.com/unnamed.owl#ABCD> }";
Query query = QueryFactory.create(sparqlQueryString) ;
QueryExecution qexec = QueryExecutionFactory.create(query, m) ; //LINE
OF CONSIDERATION
ResultSet results = qexec.execSelect() ;
ResultSetFormatter.out(results) ;
tdb.close();
dataset.close();
}
}
As per the above code snippet given, and the line marked as "LINE OF
CONSIDERATION", when i pass the OntModel m as the parameter the results are
in accordence to the inference mechanisms (such as Transitive relations)
but if I change the parameter to dataset i.e.
QueryExecution qexec = QueryExecutionFactory.create(query, dataset) ;
and hence execute the query, the results are not the same.
As per my observation the a Query made to the Dataset/TDB directly is
unable to provide inference mechanisms as provided by the OntModel, even
when the TDB creation is done as follows:
public static OntModel createTDBFromOWL(){
Dataset dataset =
TDBFactory.createDataset("./MyDatabases/OntologyTDB") ;
Model m = dataset.getDefaultModel();
OntModel om =ModelFactory.createOntologyModel(
OntModelSpec.OWL_MEM_RULE_INF, m );
FileManager.get().readModel( om,"./OWLs/MyOWLfile.owl");
return om;
}
Is there some way to create a Dataset object, which is Inference enabled,
similar to creation of an OntModel like:
OntModel om =ModelFactory.createOntologyModel(
OntModelSpec.OWL_MEM_RULE_INF, m );
so that the dataset supports inferenceing mechanisms?
On Thu, Oct 10, 2013 at 3:51 PM, Andy Seaborne <[email protected]> wrote:
> On 10/10/13 10:12, Dibyanshu Jaiswal wrote:
>
>> Hi!
>>
>> I am new to semantic web technologies, and have started with RDF/OWL for
>> making web applications.
>> Currently i have a requirement for accessing a Ontology (OntModel with
>> OWLModelSpec.OWL_MEM_RULE_INF) from an OWL file.I am also able to Store in
>> local TDB, all done by JENA 2.11.0. Thanks to the Nice API and Tutorial
>> provided for the same.
>> I need to fire SPARQL queries on the model to get some fruitful results.
>> Once the TDB is created, in order to fire search query on the same, the
>> results are not as expected.
>>
>> As per my SPARQL qurey, when directly made to the TDB Dataset, does not
>> returns results (i.e. results with inference rules) accordingly. Where as
>> If the same query is fired on the OntModel (loaded from the TDB, with
>> OWLModelSpec.OWL_MEM_RULE_INF ) itself the results are found to be as
>> expected.
>>
>
> Generally, showing the details of what you are doing makes it easier for
> people to provide answers. The details matter :-)
>
>
>
>> How do I solve the problem of making queries directly to the Dataset and
>> not to OntModel with inference rule enabled?
>>
>
> Inference is a characteristic of the model (in RDF inference is within
> models/graphs, not between graphs).
>
> You need to create an ont model backed by a graph from the TDB store.
>
> Andy
>
>
> Please help!!
>> Thanks in Advance!!
>>
>>
>
--
*Dibyanshu Jaiswal*
Mb: +91 9038304989
Mb: +91 9674272265
