class hierarchy of Notation3

Question

i have a simple notation3 ontology

@prefix my: <http://www.codeproject.com/KB/recipes/n3_notation#>.
@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .



    my:spec a rdfs:Class.
    my:security a rdfs:Class; rdfs:subClassOf my:spec .

    my:bluetooth a my:security;
    my:preferedby my:BusinessPerson;
    my:name "bluetooth".

im trying to define class specand define security class as a subclass of spec.

this is my sparql query im using with the help of dotNetRdf library

PREFIX my: <http://www.codeproject.com/KB/recipes/n3_notation#>
SELECT ?name
WHERE {
    [ a my:spec;
        my:preferedby my:BusinessPerson;
        my:name ?name].
}";

according to class hierarchy this query should return 'bluetooth' as an answer since security is a subclass of spec (according to my knowledge) . but so far no result. can some one help me with this where i have done my mistake ? thanks in advanced

Answer 1

im trying to define class specand define security class as a subclass of spec.

I think you've done this part correctly.

according to class hierarchy this query should return 'bluetooth' as an answer since security is a subclass of spec (according to my knowledge) .

To infer that the instance which is asserted to be of type security is also an instance of type spec, you need at least RDFS inferencing. SPARQL doesn't provide that directly, though many endpoints and triple stores may have some support for it. However, some basic forms of inference can be encoded with SPARQL, and you can get your query to work in this case. You just need to adjust your query (and add the rdfs: prefix) to this:

SELECT ?name WHERE {
    [ a rdfs:subClassOf*/my:spec;
        my:preferedby my:BusinessPerson;
        my:name ?name].
}

This literally says that you want to find an instance of a class C where C is connected by a chain of rdfs:subClassOf links of length zero or more to my:spec. In this case, that means everything that's either a security or a spec.

For more about doing RDFS and OWL inferencing in SPARQL, you may find some of these questions and answers helpful:

• Using SPARQL for limited RDFS and OWL reasoning
• Sparql query Subclass or EquivalentTo
• how to do reasoning in Jena via Sparql Query