SPARQL native engine: syntax error in SQL translation

Posted by Patzy on
URL: http://owlready.306.s1.nabble.com/SPARQL-native-engine-syntax-error-in-SQL-translation-tp2777.html

Hello,

I'm trying to use OWLReady2 with SPARQL queries but while some queries are properly translated to SQL but I have a problem with the following one:

    PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
    PREFIX xsd: <http://www.w3.org/2001/XMLSchema#>
    PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
    PREFIX owl: <http://www.w3.org/2002/07/owl#>
    PREFIX domain: <http://diana/camrest.owl#>
    SELECT ?name ?address ?area ?food ?phone ?pricerange ?postcode ?signature ?description WHERE {
    VALUES ?name {<http://diana/camrest.owl#the%20nirala>}.
    OPTIONAL {<http://diana/camrest.owl#the%20nirala> domain:address ?address.}
    OPTIONAL {<http://diana/camrest.owl#the%20nirala> domain:area ?area.}
    OPTIONAL {<http://diana/camrest.owl#the%20nirala> domain:food ?food.}
    OPTIONAL {<http://diana/camrest.owl#the%20nirala> domain:phone ?phone.}
    OPTIONAL {<http://diana/camrest.owl#the%20nirala> domain:pricerange ?pricerange.}
    OPTIONAL {<http://diana/camrest.owl#the%20nirala> domain:postcode ?postcode.}
    OPTIONAL {<http://diana/camrest.owl#the%20nirala> domain:signature ?signature.}
    OPTIONAL {<http://diana/camrest.owl#the%20nirala> domain:description ?description.}
    }

It is apparently translated to this:

SELECT IN (360), q1.o, q1.d, q2.o, q3.o, q4.o, q4.d, q5.o, q6.o, q6.d, q7.o, q7.d, q8.o, q8.d FROM datas q1 ON (q1.s=360 AND q1.p=314) LEFT JOIN objs q2 ON (q2.s=360 AND q2.p=308) LEFT JOIN objs q3 ON (q3.s=360 AND q3.p=303) LEFT JOIN datas q4 ON (q4.s=360 AND q4.p=316) LEFT JOIN objs q5 ON (q5.s=360 AND q5.p=306) LEFT JOIN datas q6 ON (q6.s=360 AND q6.p=317) LEFT JOIN datas q7 ON (q7.s=360 AND q7.p=318) LEFT JOIN datas q8 ON (q8.s=360 AND q8.p=315)

Which generates the following error:

Traceback (most recent call last):
  File "test_owlready.py", line 88, in <module>
    print(list(r))
  File "/home/m0rg/orange/dialog-platform/poc-rdf/env/lib/python3.7/site-packages/owlready2/sparql/main.py", line 335, in execute
    for l in PreparedQuery.execute(self, params):
  File "/home/m0rg/orange/dialog-platform/poc-rdf/env/lib/python3.7/site-packages/owlready2/sparql/main.py", line 331, in execute
    return self.world.graph.execute(self.sql, sql_params)
sqlite3.OperationalError: near "IN": syntax error

Note that the concerned query is working with rdflib.
I'm using owlready 0.36 on python3.7, any idea of what may cause the problem ?