Andy, Thanks for your helpful and prompt response. The potential difference between your and our settings could be that you are directly setting the data file while we have data inserted into store by means of INSERT queries (let me use your more compact URIs):
== D.trig @base <http://example/> . <g1> { <s> <p> <x> } <g2> { <x> <q> <o> } vs. INSERT DATA { GRAPH <http://g1> { <s> <p> <x> . } } INSERT DATA { GRAPH <http://g2> { <x> <q> <o> . } } I am not sure whether it makes any difference or not? Regarding old version of the software, we are constrained with limited possibility to frequently switch to the latest Java versions. As much as we know, the versions of Jena and TDB are the latest that work on Java 5. More recent versions require Java 6. Thanks, Milorad >________________________________ > From: Andy Seaborne <a...@apache.org> >To: users@jena.apache.org >Sent: Thursday, March 28, 2013 3:36 PM >Subject: Re: graph merge in SPARQL > >On 28/03/13 13:14, Milorad Tosic wrote: >> Hi, >> >> The SPARQL standard states that multiple FROM clauses in a single >> SPARQL query should be interpreted as a graph merge operation. But, I >> get strange behavior in this case not as specified. At the end of the >> message I first include results of a illustrative example that >> indicates that graphs are not merged followed byJava code for >> the same example. >> What I am doing wrong? What should be done to make the graph merge >> working? We use jena-2.6.4 and tdb-0.8.9. >> > >Old versions, pre-Apache. It seems to work for me in current TDB. > >A simple test case of your setup is one data file, one query. > >== D.trig >@base <http://example/> . > ><g1> { <s> <p> <x> } ><g2> { <x> <q> <o> } >== Q.rq >BASE <http://example/> >SELECT * >FROM <g1> >FROM <g2> >{ > ?s <p> ?x . > ?x <q> <o> >} >== > tdbquery --mem D.trig --file Q.rq >==> >------------- >| s | x | >============= >| <s> | <x> | >------------- > >(I also did the same with your data, converted, successfully but it's a >bit wide for email) > >This is with current TDB 0.10.0 which supports --mem for quick, >in-memory testing. It creates and loads a TDB database using a RAM disk >- otherwise TDB query execution is the same as disk. > >Otherwise: You will need > >rm -rf DBX >tdbloader --loc=DBX D.trig >tdbquery --loc=DBX --file Q.rq > > Andy > >(I haven't checked the java code is working correctly) > > >> Thanks, >> Milorad >> >> =================================================================== >> START >> Deleting directory: C:/DatasetGraphsMergeTest >> creating directory: C:/DatasetGraphsMergeTest >> DIR created >> WARN [main] (SetupTDB.java:755) - No BGP optimizer >> First graph created. >> -------------------------------------------------------------------------------------------------------------------------- >> | s | p | >> o | >> ========================================================================================================================== >> | <http://test/r1> | <http://www.w3.org/2000/01/rdf-schema#subPropertyOf> | >> <http://www.w3.org/2000/01/rdf-schema#label> | >> -------------------------------------------------------------------------------------------------------------------------- >> Second graph created. >> ---------------------------------------------------------------------------------------------- >> | s | p | >> o | >> ============================================================================================== >> | <http://test/r2> | <http://www.w3.org/2000/01/rdf-schema#subPropertyOf> | >> <http://test/r1> | >> ---------------------------------------------------------------------------------------------- >> Inter graph query results. >> --------- >> | s | l | >> ========= >> --------- >> END >> >> =================================================================== >> >> >> import java.io.File; >> import java.io.IOException; >> >> import org.apache.commons.io.FileUtils; >> >> import com.hp.hpl.jena.query.Query; >> import com.hp.hpl.jena.query.Dataset; >> import com.hp.hpl.jena.query.QueryExecution; >> import com.hp.hpl.jena.query.QueryExecutionFactory; >> import com.hp.hpl.jena.query.QueryFactory; >> import com.hp.hpl.jena.query.ResultSet; >> import com.hp.hpl.jena.query.ResultSetFormatter; >> import com.hp.hpl.jena.shared.Lock; >> import com.hp.hpl.jena.tdb.TDB; >> import com.hp.hpl.jena.tdb.TDBFactory; >> import com.hp.hpl.jena.update.UpdateAction; >> import com.hp.hpl.jena.update.UpdateFactory; >> import com.hp.hpl.jena.update.UpdateRequest; >> >> public class DatasetGraphsMergeSPARQL { >> public static final String TDB_DIR = "C:/DatasetGraphsMergeTest";//path >>on locval HDD for TDB store >> public static final boolean DELETE_EXISTING_TDB = true;//if TDB already >>exist should we delete it >> >> public static final String Q_CreateGraph1 = >> "INSERT DATA { " + >> " GRAPH <http://g1> { " + >> " <http://test/r1> >><http://www.w3.org/2000/01/rdf-schema#subPropertyOf> " + >> " <http://www.w3.org/2000/01/rdf-schema#label> . " + >> " }" + >> "}"; >> public static final String Q_CreateGraph2 = >> "INSERT DATA { " + >> " GRAPH <http://g2> { " + >> " <http://test/r2> >><http://www.w3.org/2000/01/rdf-schema#subPropertyOf> " + >> " <http://test/r1> . " + >> " }" + >> "}"; >> public static final String Q_TestEmpty1 = >> "SELECT ?s ?p ?o " + >> "FROM <http://g1> " + >> "{ " + >> " ?s ?p ?o . " + >> "}"; >> public static final String Q_TestEmpty2 = >> "SELECT ?s ?p ?o " + >> "FROM <http://g2> " + >> "{ " + >> " ?s ?p ?o . " + >> "}"; >> public static final String Q_TestInterGraphPath = >> "SELECT ?s ?l " + >> "FROM <http://g1> " + >> "FROM <http://g2> " + >> "{ " + >> " ?s <http://www.w3.org/2000/01/rdf-schema#subPropertyOf> ?l . " + >> " ?l <http://www.w3.org/2000/01/rdf-schema#subPropertyOf> " + >> " <http://www.w3.org/2000/01/rdf-schema#label> . >>" + >> "}"; >> >> >> public static void main(String[] args) throws Exception{ >> Dataset m_dataset; >> System.out.println("START"); >> >> m_dataset = initDataset(); >> updateDataset(m_dataset, Q_CreateGraph1); >> System.out.println("First graph created."); >> selectDataset(m_dataset, Q_TestEmpty1); >> >> updateDataset(m_dataset, Q_CreateGraph2); >> System.out.println("Second graph created."); >> selectDataset(m_dataset, Q_TestEmpty2); >> >> System.out.println("Inter graph query results."); >> selectDataset(m_dataset, Q_TestInterGraphPath); >> >> System.out.println("END"); >> } >> >> public static Dataset initDataset() throws IOException{ >> //Initializing Dataset//Creating Directory for TDB >> File tdbDir = new File(TDB_DIR); >> >> if(DELETE_EXISTING_TDB && tdbDir.exists()){ >> System.out.println("Deleting directory: " + TDB_DIR); >> FileUtils.deleteDirectory(tdbDir); >> } >> if (!tdbDir.exists()){ >> System.out.println("creating directory: " + TDB_DIR); >> boolean result = tdbDir.mkdir(); >> if(result){ >> System.out.println("DIR created"); >> } >> } >> //Initializing Dataset >> return TDBFactory.createDataset(tdbDir.getPath()); >> } >> >> public static void updateDataset(Dataset dataset, String querystr){ >> dataset.getLock().enterCriticalSection(Lock.WRITE); >> try { >> UpdateRequest updateRequest = UpdateFactory.create(querystr); >> UpdateAction.execute(updateRequest, dataset); >> }catch (Exception e){ >> System.out.println(e); >> } finally { >> TDB.sync(dataset); >> dataset.getLock().leaveCriticalSection(); >> } >> } >> >> public static void selectDataset(Dataset dataset, String querystr){ >> //SPARQL QUERY is handled here >> Query query = QueryFactory.create(querystr); >> dataset.getLock().enterCriticalSection(Lock.READ) ; >> try { >> QueryExecution qexec = QueryExecutionFactory.create(query, >>dataset) ; >> ResultSet results = qexec.execSelect() ; >> ResultSetFormatter.out(System.out, results); >> qexec.close(); >> } finally { >> dataset.getLock().leaveCriticalSection(); >> } >> } >> >> } >> > > > >
