Dear all,
I am having trouble using certain keywords of Jena ARQ to query virtuoso
over the Virtuoso Jena Provider.
In particular, my queries require the use of the keywords LET, NOT EXISTS,
and IRI.
For example I tried to execute the following Code:
VirtGraph set = new VirtGraph
("jdbc:virtuoso://localhost:1111/charset=UTF-8/log_enable=2", "dba", "dba");
Model model = new VirtModel(set);
String queryString =
"SELECT ?s ?o ?now " +
" FROM <http://localhost/mediawiki> " +
" WHERE{" +
" ?s ?p ?o . " +
"LET(?now := true)" +
"}";
Query query =
QueryFactory.create(queryString,Syntax.syntaxARQ);
QueryExecution vqe =
VirtuosoQueryExecutionFactory.create(query, model);
ResultSet results = vqe.execSelect();
System.out.print(ResultSetFormatter.asText(results));
Which returns the following error message:
Exception in thread "main" com.hp.hpl.jena.shared.JenaException: Can not
create ResultSet.:virtuoso.jdbc3.VirtuosoException: SQ074: Line 12: SP030:
SPARQL compiler, line 10: syntax error at 'LET' before '('
at virtuoso.jena.driver.VirtuosoQueryExecution.execSelect(Unknown
Source)
at VirtuosoSPARQLExample1.main(VirtuosoSPARQLExample1.java:73)
When I use QueryExecutionFactory instead of VirtuosoQueryExecutionFactory I
get the following error message:
Exception in thread "main" com.hp.hpl.jena.shared.JenaException: Can not
create QueryIterator.:virtuoso.jdbc3.VirtuosoException: SQ074: Line 12:
SP030: SPARQL compiler, line 10: syntax error at 'LET' before '('
at virtuoso.jena.driver.VirtuosoQueryEngine.eval(Unknown Source)
at
com.hp.hpl.jena.sparql.engine.QueryEngineBase.evaluate(QueryEngineBase.java:
124)
at
com.hp.hpl.jena.sparql.engine.QueryEngineBase.createPlan(QueryEngineBase.jav
a:98)
at
com.hp.hpl.jena.sparql.engine.QueryEngineBase.getPlan(QueryEngineBase.java:8
6)
at
virtuoso.jena.driver.VirtuosoQueryEngine$VirtQueryEngineFactory.create(Unkno
wn Source)
at
com.hp.hpl.jena.sparql.engine.QueryExecutionBase.getPlan(QueryExecutionBase.
java:266)
at
com.hp.hpl.jena.sparql.engine.QueryExecutionBase.startQueryIterator(QueryExe
cutionBase.java:243)
at
com.hp.hpl.jena.sparql.engine.QueryExecutionBase.execResultSet(QueryExecutio
nBase.java:248)
at
com.hp.hpl.jena.sparql.engine.QueryExecutionBase.execSelect(QueryExecutionBa
se.java:94)
at VirtuosoSPARQLExample1.main(VirtuosoSPARQLExample1.java:73)
Simple queries without the use of Jena ARQ specific keywords work fine!
I am using Virtuoso Open Source 6.1.4 and Jena 2.6.2 with ARQ 2.8.3. The
virt_jena.jar is for Jena 2.6.2 [Build 1.5].
Thank you for any help!
Christian
------------------------------------------
Dipl.-Kfm. Christian Fürber
Professur für Allgemeine BWL, insbesondere E-Business
e-business & web science research group
Universität der Bundeswehr München
e-mail: c.fuer...@unibw.de
www: http://www.unibw.de/ebusiness/
skype: c.fuerber
twitter: cfuerber
