Andy, thank you very much! BTW, Jena documentation is not very detailed...
Thanks. Vadim. On Tue, May 3, 2016 at 12:50 PM, Andy Seaborne <[email protected]> wrote: > 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. >> >> >> >> >> >> >> >> > -- Vadim Shumilin
