使用Protoge中的SPARQL查询标签来查询我自己的本体中的元素。

Question

我有一个本体，我正试图为它编写SPARQL查询。

我正在使用本体IRI (http:/www.semanticweb.orgchrisontologies20202dis-coursework-ontology)显示在Active ontology选项卡上，在下面的查询中定义PREFIX值。

PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
PREFIX owl: <http://www.w3.org/2002/07/owl#>
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
PREFIX xsd: <http://www.w3.org/2001/XMLSchema#>
PREFIX chris: <http://www.semanticweb.org/chris/ontologies/2020/2/dis-coursework-ontology#>

SELECT ?class ?activity
    WHERE { ?class chris:hasActivity ?activity }

当我运行这个查询时，什么都没有返回，但是当我把本体输出为RDF格式时，我可以看到我想要返回的实例。

<owl:Class rdf:about="http://www.semanticweb.org/chris/ontologies/2020/2/dis-coursework-ontology#SportsHallBooking">
        <rdfs:subClassOf rdf:resource="http://www.semanticweb.org/chris/ontologies/2020/2/dis-coursework-ontology#BookableTimetable"/>
        <rdfs:subClassOf>
                <owl:Restriction>
                        <owl:onProperty rdf:resource="http://www.semanticweb.org/chris/ontologies/2020/2/dis-coursework-ontology#hasActivity"/>
                        <owl:someValuesFrom rdf:resource="http://www.semanticweb.org/chris/ontologies/2020/2/dis-coursework-ontology#Badminton"/>
                </owl:Restriction>
        </rdfs:subClassOf>
        <rdfs:subClassOf>
        </rdfs:subClassOf>
        <rdfs:subClassOf>
                <owl:Restriction>
                        <owl:onProperty rdf:resource="http://www.semanticweb.org/chris/ontologies/2020/2/dis-coursework-ontology#hasActivity"/>
                        <owl:someValuesFrom rdf:resource="http://www.semanticweb.org/chris/ontologies/2020/2/dis-coursework-ontology#Football"/>
                </owl:Restriction>
        </rdfs:subClassOf>
</owl:Class>

activity SportsHallBooking

class /www.semanticweb.orgchrisontologies20202dis-coursework-ontology）显示在Active ...

感谢Stanislav的回答。