如何在给定名称的Jena TDB上查询模型

Question

public void store(){
    String directory = "C:\\tdb";
    String source = "C:\\file1.rdf";
    String source1 = "C:\\file2.rdf";
    Dataset dataset = openTDB(directory);
    Model tdb = loadModel(source, dataset);
    dataset.addNamedModel("File1", tdb);

    Model tdb1 = loadModel(source1, dataset);
    dataset.addNamedModel("File2", tdb1);

    queryTDB(tdb, dataset);
    queryTDB(tdb1, dataset);

    tdb.close();
    tdb1.close();
    dataset.close();
}

public Dataset openTDB(String directory) {
    // open TDB dataset
    Dataset dataset = TDBFactory.createDataset(directory);
    return dataset;
}

public Model loadModel(String source, Dataset dataset) {

    Model tdb = dataset.getDefaultModel();
    FileManager.get().readModel( tdb, source, "RDF/XML" );
    return tdb;
}

public void queryTDB(Model tdb, Dataset dataset) {

    String queryStr = "SELECT * { ?s ?p ?o }";

    Query query = QueryFactory.create(queryStr);
    QueryExecution qexec = QueryExecutionFactory.create(query, tdb);
    /*Execute the Query*/
    ResultSet results = qexec.execSelect();
    ResultSetFormatter.out(results) ;
    qexec.close();
}

这段代码起作用，但我想知道我如何只针对名为“file1”（或“file2”）的模型获得查询结果。事实上，使用这样编写的查询，我得到了两个模型的结果。

我怎么才能意识到？

Answer 1

select * {
  graph ?g {  
    ?s ?p ?o
  }
}

select *
from named <name-of-graph>
{
  ?s ?p ?o
}

select * {
  graph <name-of-graph> {  
    ?s ?p ?o
  }
}