[redland-dev] problem with OPTIONAL in sparql

[Benno Blumenthal]

Hello All,

I am working with SPARQL through rasqal 0.9.10 in redland-1.0.2 under 
linux  2.4.21-27.0.2.ELsmp.

When I try the query on my triple set

PREFIX  iridl: <http://iridl.ldeo.columbia.edu/ontologies/iridl.owl#>
PREFIX iribib: <http://iridl.ldeo.columbia.edu/ontologies/iribib.owl#>
PREFIX rdfcache: <http://iridl.ldeo.columbia.edu/ontologies/rdfcache.owl#>
SELECT ?y ?x
WHERE { ?x iridl:hasSemantics ?y . ?y a iridl:Person  .
            ?z iridl:isContainerOf ?x  .
            FILTER (bound(?z))
}

I get results.

When I change it to

PREFIX  iridl: <http://iridl.ldeo.columbia.edu/ontologies/iridl.owl#>
PREFIX iribib: <http://iridl.ldeo.columbia.edu/ontologies/iribib.owl#>
PREFIX rdfcache: <http://iridl.ldeo.columbia.edu/ontologies/rdfcache.owl#>
SELECT ?y ?x
WHERE { ?x iridl:hasSemantics ?y . ?y a iridl:Person  .
            OPTIONAL { ?z iridl:isContainerOf ?x } .
            FILTER (bound(?z))
}

I get nothing.

The query I really want is a more complicated version of

PREFIX  iridl: <http://iridl.ldeo.columbia.edu/ontologies/iridl.owl#>
PREFIX iribib: <http://iridl.ldeo.columbia.edu/ontologies/iribib.owl#>
PREFIX rdfcache: <http://iridl.ldeo.columbia.edu/ontologies/rdfcache.owl#>
SELECT ?y ?x
WHERE { ?x iridl:hasSemantics ?y . ?y a iridl:Person  .
            OPTIONAL { ?z iridl:isContainerOf ?x . iridl:hasSemantics ?a 
. ?a a iridl:Person } .
            FILTER (!bound(?z))
}

in case you were wondering....


Is this clearly a bug, or am I missing something simple?  If it is a 
bug, how can I usefully contribute a bug report or where could I look to 
try to fix this?

Benno


-- 
Dr. M. Benno Blumenthal          benno at iri.columbia.edu
International Research Institute for climate prediction
The Earth Institute at Columbia University
Lamont Campus, Palisades NY 10964-8000   (845) 680-4450