SPARQL list literals of selected OWL Datatype - sparql

Question

How to list all literals of only selected OWL datatype (here :VisibilityKind) in SPARQL? The OWL datatype definition of VisibilityKind is:
DatatypeDefinition( :VisibilityKind
DataOneOf( "public"^^xsd:string "private"^^xsd:string "package"^^xsd:string )
)

Answer 1

With SPARQL, you can get all the literals that have a certain datatype IRI. For instance, assuming you have data with literals such as "public"^^:VisibilityKind, you can write:
SELECT ?literal WHERE {
?s ?p ?literal .
FILTER (datatype(?literal) = :VisibilityKind)
}
But this is certainly not what you want because you probably do not have literals with this datatype IRI. What you would probably like is something that could roughly be formulated as:
SELECT ?literal WHERE {
?s ?p ?literal .
FILTER (isInDatatype(?literal,:VisibilityKind))
}
where isInDatatype checks if the value associated with ?o belongs to the value space of :VisibilityKind. However, such function does not exist in standard SPARQL 1.1. Moreover, even if it existed, it would require the query engine to understand the semantics of OWL 2 and do reasoning. So you would need a SPARQL engine that implements the OWL 2 DL entailment regime and you'd have to hack a bit the query to get what you want:
SELECT ?literal WHERE {
?s ?p ?literal .
[] a :VisibilityKind;
:owl:sameAs ?literal;
FILTER (isLiteral(?literal))
}
If you want to find implementations of SPARQL 1.1 Entailment regimes, you could take a look at the implementation reports collected by the SPARQL working group.

Answer 2

To answer directly, you need to search for all values in the owl:oneOf list:
SELECT ?resource ?value
WHERE {
:VisibilityKind owl:equivalentClass / owl:oneOf / ( rdf:rest*/rdf:first ) ?value .
?resource ?prop ?value .
}
However, there is a caveat - other properties could have the value "public" "private" or "package". To ensure that you're getting only the values of :VisibilityKind, define that datatype as a range of properties that use the datatype:
{ :someProp rdfs:domain :VisibilityKind }
Then use the following query to get all properties that define :VisibilityKind in the range:
SELECT ?resource ?value
WHERE {
?prop rdfs:range :VisibilityKind .
?resource ?prop ?value
}