我试图进行SPARQL查询,该查询返回Turtle文件的每个数据属性的不同值的数量。我想知道每个值的名称是什么,以及每个值重复多少次。我创建了一个简单的本体来测试:
@prefix owl: <http://www.w3.org/2002/07/owl#> .
@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
@prefix uni: <http://www.example.com/university#> .
@prefix xml: <http://www.w3.org/XML/1998/namespace> .
@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .
@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .
@base <http://www.example.com/university> .
<http://www.example.com/university> rdf:type owl:Ontology .
#################################################################
# Classes
#################################################################
### http://www.example.com/university#Lecturer
:Lecturer rdf:type owl:Class ;
rdfs:subClassOf :Person .
### http://www.example.com/university#Person
:Person rdf:type owl:Class .
#################################################################
# Individuals
#################################################################
### http://www.example.com/university#Lecturer1
:Lecturer1 rdf:type owl:NamedIndividual ,
:Lecturer ;
:first_name "John"^^xsd:string ;
:last_name "Coles"^^xsd:string ;
:staffID "234"^^xsd:int .
### http://www.example.com/university#Lecturer2
:Lecturer2 rdf:type owl:NamedIndividual ,
:Lecturer ;
:first_name "John"^^xsd:string ;
:last_name "Doe"^^xsd:string ;
:staffID "89387"^^xsd:int .
### http://www.example.com/university#lecturer3
:lecturer3 rdf:type owl:NamedIndividual ,
:Lecturer ;
:first_name "John"^^xsd:string ;
:last_name "Doe"^^xsd:string ;
:staffID "7658"^^xsd:int .
#################################################################
# General axioms
#################################################################
[ rdf:type owl:AllDisjointClasses ;
owl:members (
:Lecturer
)
] .
这是我正在使用的SPARQL查询:
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 uni: <http://www.example.com/university#>
select distinct ?ind ?property ?value (count(?value) as ?noOfDistinctValues) where {
?ind rdf:type uni:Lecturer .
?ind ?property ?value .
?property a owl:DatatypeProperty
}
group by ?ind ?property ?value
这是结果(计数对我而言没有意义),我确定查询有问题:
ind property value noOfDistinctValues
------------------------------------------------------------
lecturer2 staffID 89387 6
lecturer2 first_name John 8
lecturer2 last_name Doe 8
lecturer1 staffID 234 6
lecturer1 first_name John 8
lecturer1 last_name Coles 8
lecturer3 staffID 7658 6
lecturer3 first_name John 8
lecturer3 last_name Doe 8
我正在寻找:
property value noOfDistinctValues
------------------------------------------
staffID 89387 1
first_name John 3
last_name Doe 2
staffID 234 1
last_name Coles 1
staffID 7658 1
我什至不知道它返回了什么。我也是Ontology和SPARQL
的新手非常感谢您的帮助
感谢@AKSW,我得以解决我的问题。这工作:
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 uni: <http://www.example.com/university#>
select ?property (str(?value) as ?valueLiteral) (str(count(distinct ?ind)) as
?noOfValueOccurrences)
where { ?ind rdf:type uni:Lecturer.
?ind ?property ?value.
?property a owl:DatatypeProperty .}
group by ?property ?value
order by ?property