SPARQL - Query based on some property - sparql

Question

I want to get all the pizza names which has cheese toppings but the result shows (_:b0) which is kind of an owl restriction following is my query
PREFIX pizza: <http://www.co-ode.org/ontologies/pizza/pizza.owl#>
SELECT ?X WHERE {
?X rdfs:subClassOf* [
owl:onProperty pizza:hasTopping ;
owl:someValuesFrom pizza:CheeseTopping
]
}
using Pizza ontology from stanford

Answer 1

This works (Without reasoning enabled)
PREFIX pizza: <http://www.co-ode.org/ontologies/pizza/pizza.owl#>
SELECT ?X ?topping WHERE {
?X rdfs:subClassOf ?Y .
?Y owl:someValuesFrom ?topping .
?topping rdfs:subClassOf* pizza:CheeseTopping
}
ORDER BY ?X
Some are listed more than once as they could contain more than one CheeseTopping. To remove duplicates:
PREFIX pizza: <http://www.co-ode.org/ontologies/pizza/pizza.owl#>
SELECT DISTINCT ?X WHERE {
?X rdfs:subClassOf ?Y .
?Y owl:someValuesFrom ?topping .
?topping rdfs:subClassOf* pizza:CheeseTopping
}
ORDER BY ?X
This works if you enable a reasoner:
PREFIX pizza: <http://www.co-ode.org/ontologies/pizza/pizza.owl#>
SELECT DISTINCT ?X WHERE {
?X rdfs:subClassOf pizza:CheeseyPizza
}
Ref:
Used the pizza ontology from here: http://protege.stanford.edu/ontologies/pizza/pizza.owl

Answer 2

That query works but is really complex and might be incomplete because some pizzas use complex OWL constructs:
PREFIX pizza: <http://www.co-ode.org/ontologies/pizza/pizza.owl#>
SELECT DISTINCT ?pizza WHERE {
{
?pizza rdfs:subClassOf* pizza:Pizza .
?pizza owl:equivalentClass|rdfs:subClassOf [
rdf:type owl:Restriction ;
owl:onProperty pizza:hasTopping ;
owl:someValuesFrom/rdfs:subClassOf* pizza:CheeseTopping
]
} UNION {
?pizza owl:equivalentClass _:b0 .
_:b0 rdf:type owl:Class ;
owl:intersectionOf _:b1 .
_:b1 (rdf:rest)*/rdf:first ?otherClass.
?otherClass rdf:type owl:Restriction ;
owl:onProperty pizza:hasTopping ;
owl:someValuesFrom/rdfs:subClassOf* pizza:CheeseTopping
}
}