Hi Vadim,
A SPARQL query runs against a dataset and that what your created with
the N-Quads files.
But a dataset is not a model.
A model is just one graph.
Read the remote data into a dataset with:
Dataset ds = RDFDataMgr.loadDataset(url) ;
...
QueryExecutionFactory.create(query, ds);
...
What is happening is that at:
model.read(url);
only the default graph of the dataset at "http://localhost:3030/ds"; is
put in the model. Models are graphs (the name reflects the older 2004
RDF terminology)
Andy
On 03/05/16 07:36, Vadim Shumilin wrote:
1) I use Fuseki2.
2) I have same test data
a) as triples in rdf file
b) as quads in nq file with graph name
from browser -- http://localhost:3030
- I uploaded the data to persistent dataset
- I see that my data successfully stored.
- I performed simple queries
#1)
SELECT ?subj ?pred ?obj WHERE { ?subj ?pred ?obj }
#2)
SELECT ?subj ?pred ?obj WHERE {
GRAPH ?g { ?subj ?pred ?obj }
}
both queries succeeded and I saw valid results.
OK, now I try to perform same queries from java program.
Here is my code:
Model model = ModelFactory.createDefaultModel();
String url = "http://localhost:3030/ds";;
model.read(url);
String RQuery = ...; //// <<< query #1 or query #2
Query query = QueryFactory.create(RQuery);
QueryExecution qe = QueryExecutionFactory.create(query, model);
ResultSet rs = qe.execSelect();
int count=0;
while (rs.hasNext())
{
QuerySolution qsol = rs.nextSolution();
++count;
}
And I have proper count for query #1 and count==0 for query #2.
Please, what is wrong with my code.
Thanks.
