如何计算不同值的数量、它们的名称以及每个数据出现的次数属性 SPARQL

Question

我正在尝试进行 SPARQL 查询，returns 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了多少次。我创建了一个简单的 ontology 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（计数对我来说没有意义），我确定我的查询有问题：

    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

我在找什么：

property     value     noOfDistinctValues 
------------------------------------------
staffID      89387         1               
first_name   John          3                
last_name    Doe           2                
staffID      234           1                
last_name    Coles         1                
staffID      7658          1

我什至不确定它被退回是什么意思。我也是 Ontology 和 SPARQL

的新手

非常感谢你的帮助

Answer 1

感谢@AKSW，我能够解决我的问题。这有效：

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

如何计算不同值的数量、它们的名称以及每个数据出现的次数属性 SPARQL

How to count the number of distinct values, their names and the number of times each appeared per data property SPARQL

owl

ontology

sparql

protege

turtle-rdf

如何计算不同值的数量、它们的名称以及每个数据出现的次数 属性 SPARQL

How to count the number of distinct values, their names and the number of times each appeared per data property SPARQL

owl

ontology

sparql

protege

turtle-rdf

如何计算不同值的数量、它们的名称以及每个数据出现的次数属性 SPARQL