Is it possible, to use property path with reified rdf triples?
I like to get all superclasses of a specified class (stored in ?class
).
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
SELECT ?class ?superclass ?supersuperclass ?supersupersuperclass
WHERE{
{
?s rdf:subject ?class .
?s rdf:predicate rdfs:subClassOf .
?s rdf:object ?superclass .
OPTIONAL {
?s1 rdf:subject ?superclass .
?s1 rdf:predicate rdfs:subClassOf .
?s1 rdf:object ?supersuperclass .
}
OPTIONAL {
?s2 rdf:subject ?supersuperclass .
?s2 rdf:predicate rdfs:subClassOf .
?s2 rdf:object ?supersupersuperclass .
}
}
}
You can use intermediate queries, first to dereify the statements:
CONSTRUCT {
?s a rdfs:Class .
?o a rdfs:Class .
?s rdfs:subClassOf ?o .
}
WHERE {
?t a rdf:Statement .
?t rdf:object ?o .
?t rdf:predicate rdfs:subClassOf .
?t rdf:subject ?s .
}
Then to obtain all of the subclass relations:
SELECT ?s ?o
WHERE {
?s a rdfs:Class .
?s rdfs:subClassOf* ?o .
}
If you know that classes are not interlinked by other predicates, you may use paths:
SELECT ?s ?o
WHERE {
?s a rdfs:Class .
?o a rdfs:Class .
?s (^rdf:subject/rdf:object)* ?o .
}