On 12/05/14 12:54, Hugh Williams wrote:
Hi Rob,
What is not SPARQL 1.1 about the query being run ie
select distinct ?T1 ?T2 count(*) from <http://dbpedia.org>
where
{
?s1 <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> ?T1.
?s2 <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> ?T2.
?s1 <http://dbpedia.org/property/spouse> ?s2.
?s2 <http://dbpedia.org/property/birthPlace> ?obj.
FILTER(REGEX(?T1, "http://dbpedia.org/ontology/";)).
FILTER(REGEX(?T2, "http://dbpedia.org/ontology/";)).
}
group by ?T1 ?T2
The only potential problem I see is the "count(*)" which maybe have to be changed to be
"(count(*) as ?count)" as in the specs if this is not deemed to be SPARQL 1.1 ie
It is not legal SPARQL 1.1.
select distinct ?T1 ?T2 (count(*) as ?count) from <http://dbpedia.org>
where
{
?s1 <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> ?T1.
?s2 <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> ?T2.
?s1 <http://dbpedia.org/property/spouse> ?s2.
?s2 <http://dbpedia.org/property/birthPlace> ?obj.
FILTER(REGEX(?T1, "http://dbpedia.org/ontology/";)).
FILTER(REGEX(?T2, "http://dbpedia.org/ontology/";)).
}
group by ?T1 ?T2
Which seems to work against other endpoints ...
Would be nice if the Jena SPARQL validator at
http://www.sparql.org/validator.html worked to check ?
What "would be nice"?
It correctly shows it to be an error unless you enable extensions.
I note in the code Jena snippet below the call "QueryFactory.create(query,
Syntax.syntaxSPARQL_11);" , which seems to be forcing the invocation of the Jena Parser, but
if the "Syntax.syntaxSPARQL_11" param is removed then it should bypass the Jena parser
and pass Query on to Virtuoso as is , as detailed at:
http://virtuoso.openlinksw.com/dataspace/doc/dav/wiki/Main/VirtJenaProvider#Bypass%20Jena/ARQ%20parser
is 'query' the same in both code snippets?
Andy
Best Regards
Hugh Williams
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On 12 May 2014, at 09:17, Rob Vesse <[email protected]> wrote:
Yes, though the Virtuoso specific syntax shown there is not legal SPARQL
See Aggregates (http://www.w3.org/TR/sparql11-query/#aggregates) in the
SPARQL 1.1 specification which Jena fully supports
Rob
On 12/05/2014 05:49, "Md Mizanur Rahoman" <[email protected]> wrote:
Dear Experts,
My question is:
Is there any Jena implementation that can execute Aggregate function like
count, sum etc? Iterative counting of all elements could an option,
however, I want to know about direct implement of below method.
such as, the below method
------------------------------
------------------------------------------------------------------------
public void queryExecutor(VirtGraph dataset) {
String query =
"select distinct ?T1 ?T2 count(*) "+
"from <http://dbpedia.org> "+
"where "+
"{ "+
"?s1 <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> ?T1. "+
"?s2 <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> ?T2. "+
"?s1 <http://dbpedia.org/property/spouse> ?s2. "+
"?s2 <http://dbpedia.org/property/birthPlace> ?obj. "+
"FILTER(REGEX(?T1, \"http://dbpedia.org/ontology/\";)). "+
"FILTER(REGEX(?T2, \"http://dbpedia.org/ontology/\";)). "+
"}"+
"group by ?T1 ?T2 ";
System.out.println(query);
Query sparql1 = QueryFactory.create(query,
Syntax.syntaxSPARQL_11);
try {
VirtuosoQueryExecution vqe1 =
VirtuosoQueryExecutionFactory.create(sparql1, dataset);
ResultSet results1 = vqe1.execSelect();
}
catch (Exception e) {
System.out.println("Error in query execution: " +
e.toString());
e.printStackTrace();
}
}
--------------------------------------------------------------------------
---------------------------------
-
Regards
Mizan
NII, Japan
---------- Forwarded message ----------
From: Md Mizanur Rahoman <[email protected]>
Date: Wed, May 7, 2014 at 7:35 PM
Subject: Group By Query in Jena Java
To: [email protected]
Dear Expert,
I want to execute a group by query in Jena. I am using Jena V2.6.4. But it
is giving exception
--------------------------------------------------------------------------
---------------------------
Exception in thread "main" com.hp.hpl.jena.query.QueryParseException:
Encountered " "count" "count "" at line 1, column 26.
--------------------------------------------------------------------------
----------------------------
And here is my method,
--------------------------------------------------------------------------
----------------------------
public void queryExecutor(VirtGraph dataset) {
String query =
"select distinct ?T1 ?T2 count(*) "+
"from <http://dbpedia.org> "+
"where "+
"{ "+
"?s1 <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> ?T1. "+
"?s2 <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> ?T2. "+
"?s1 <http://dbpedia.org/property/spouse> ?s2. "+
"?s2 <http://dbpedia.org/property/birthPlace> ?obj. "+
"FILTER(REGEX(?T1, \"http://dbpedia.org/ontology/\";)). "+
"FILTER(REGEX(?T2, \"http://dbpedia.org/ontology/\";)). "+
"}"+
"group by ?T1 ?T2 ";
System.out.println(query);
Query sparql1 = QueryFactory.create(query,
Syntax.syntaxSPARQL_11);
try {
VirtuosoQueryExecution vqe1 =
VirtuosoQueryExecutionFactory.create(sparql1, dataset);
ResultSet results1 = vqe1.execSelect();
}
catch (Exception e) {
System.out.println("Error in query execution: " +
e.toString());
e.printStackTrace();
}
}
--------------------------------------------------------------------------
---------------------------------
My question is:
* Is there any Jena version that can execute Aggregate function like
count,
sum etc?
-
Regards
Mizanur
NII, Japan
