On 23/04/13 03:10, John Liu wrote:
Hello,
I found a problem when rewriting a query by AlgebraGenerator, the
generated query becomes syntax incorrect query. Can you please advise if
this is a defect? Thanks.
The version of JENA I tested is 2.7.1
There have been various improvements and fixes in this area which you'll
find in Jena 2.10.0 and in the active development system 2.10.1-SNAPSHOT
(from the Apache snapshot maven repository)
Andy
The code I rewrite the query is:
Query query = QueryFactory./create/(queryString);
AlgebraGenerator ag =
*new*AlgebraGenerator();
Op op = ag.compile(query);
Query query2 = OpAsQuery./asQuery/(op);
The original query is:
PREFIX dcterms: <http://purl.org/dc/terms/>
PREFIX dbpedia: <http://dbpedia.org/resource/>
SELECT ?num_of_holidays ?celebrate_Chinese_New_Year WHERE {
{SELECT ?country_cat (COUNT(?holiday) as ?num_of_holidays)
WHERE {?country_cat <http://www.w3.org/2004/02/skos/core#broader>
<http://dbpedia.org/resource/Category:Public_holidays_by_country>.
?holiday dcterms:subject ?country_cat
}GROUP by ?country_cat
}
{
SELECT ?country_cat (COUNT(?holiday) as ?celebrate_Chinese_New_Year)
WHERE {
?country_cat <http://www.w3.org/2004/02/skos/core#broader>
<http://dbpedia.org/resource/Category:Public_holidays_by_country>.
?holiday dcterms:subject ?country_cat
FILTER(?holiday="http://dbpedia.org/resource/Lunar_New_Year's_Day")
}GROUP by ?country_cat
}
}
The generated query is:
SELECT ?country_cat ?celebrate_Chinese_New_Year
WHERE
{ { ?country_cat <http://www.w3.org/2004/02/skos/core#broader>
<http://dbpedia.org/resource/Category:Public_holidays_by_country> .
?holiday <http://purl.org/dc/terms/subject> ?country_cat
BIND(count(?holiday) AS ?num_of_holidays)
}
{ ?country_cat <http://www.w3.org/2004/02/skos/core#broader>
<http://dbpedia.org/resource/Category:Public_holidays_by_country> .
?holiday <http://purl.org/dc/terms/subject> ?country_cat
FILTER ( ?holiday = "http://dbpedia.org/resource/Lunar_New_Year's_Day" )
BIND(count(?holiday) AS ?celebrate_Chinese_New_Year)
}
}
GROUP BY ?country_cat
The generated query has a syntax error: "Line 5, column 12: Aggregate
expression not legal at this point".
Attached is a hava program to demonstrate the problem,
