使用 SPARQL 和 Jena 检索 OWL 类层次结构中的所有路径

Question

我有一个具有三级深度的层次结构的 RDF 图。我想owl:Thing在不使用推理器的情况下检索从类层次结构（即）的根开始到第三级中的类的所有路径。例如，我希望路径 C ₁ → C ₂ → C ₃ 是一条路径，其中每个 C _i 是层次结构^第i层的一个类。

我需要使用广度优先搜索算法检索 RDF 图中的所有路径，而不考虑图中的对象属性。

Answer 1

给定一些这样的数据（其中类名的长度表示类在层次结构中的深度）：

@prefix : <http://example.org/> .
@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .

:a a rdfs:Class .

:aa rdfs:subClassOf :a .
:ab rdfs:subClassOf :a .
:ac rdfs:subClassOf :a .

:aaa rdfs:subClassOf :aa .
:aab rdfs:subClassOf :aa .
:aac rdfs:subClassOf :aa .

:aaba rdfs:subClassOf :aab .
:aabb rdfs:subClassOf :aab .

:aba rdfs:subClassOf :ab .
:abb rdfs:subClassOf :ab .

您可以使用 SPARQL 查询来选择您要查找的路径。

使用 SPARQL 查询

您可以编写这样的 SPARQL 查询以获得以下结果：

prefix : <http://example.org/>
prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#>

select ?c1 ?c2 ?c3 where { 
  values ?c1 { :a }
  ?c1 ^rdfs:subClassOf ?c2 .
  OPTIONAL {
    ?c2 ^rdfs:subClassOf ?c3 .
  }
}
order by ?c3 ?c2 ?c1

-------------------
| c1 | c2  | c3   |
===================
| :a | :ac |      |
| :a | :aa | :aaa |
| :a | :aa | :aab |
| :a | :aa | :aac |
| :a | :ab | :aba |
| :a | :ab | :abb |
-------------------

使用相机本体

这种方法适用于评论中提到的相机本体，尽管查询需要一些扩展来处理更深的类路径。因此：

PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
PREFIX owl: <http://www.w3.org/2002/07/owl#>
PREFIX : <http://www.xfront.com/owl/ontologies/camera/#>

select * where { 
  values ?c1 { owl:Thing } 
  ?c1 ^rdfs:subClassOf ?c2 .
  OPTIONAL { 
    ?c2 ^rdfs:subClassOf ?c3 .
    OPTIONAL { 
      ?c3 ^rdfs:subClassOf ?c4 .
    }
  }
}
order by ?c4 ?c3 ?c2

-----------------------------------------------------------
| c1        | c2                | c3      | c4            |
===========================================================
| owl:Thing | :Money            |         |               |
| owl:Thing | :Range            |         |               |
| owl:Thing | :Window           |         |               |
| owl:Thing | :PurchaseableItem | :Body   |               |
| owl:Thing | :PurchaseableItem | :Lens   |               |
| owl:Thing | :PurchaseableItem | :Camera | :Digital      |
| owl:Thing | :PurchaseableItem | :Camera | :Large-Format |
-----------------------------------------------------------

使用耶拿 API

虽然上述SPARQL查询产生的，将预期从广度优先遍历顺序的路径，实际上是没有保障如何ARQ产生的结果。我们也可以直接实现广度优先搜索，使用 Jena 模型 API 来检索子类。这是一个简单的实现：

@prefix : <http://example.org/> .
@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .

:a a rdfs:Class .

:aa rdfs:subClassOf :a .
:ab rdfs:subClassOf :a .
:ac rdfs:subClassOf :a .

:aaa rdfs:subClassOf :aa .
:aab rdfs:subClassOf :aa .
:aac rdfs:subClassOf :aa .

:aaba rdfs:subClassOf :aab .
:aabb rdfs:subClassOf :aab .

:aba rdfs:subClassOf :ab .
:abb rdfs:subClassOf :ab .

[http://www.w3.org/2002/07/owl#Thing]
[http://www.w3.org/2002/07/owl#Thing, http://www.xfront.com/owl/ontologies/camera/#PurchaseableItem]
[http://www.w3.org/2002/07/owl#Thing, http://www.xfront.com/owl/ontologies/camera/#Window]
[http://www.w3.org/2002/07/owl#Thing, http://www.xfront.com/owl/ontologies/camera/#Range]
[http://www.w3.org/2002/07/owl#Thing, http://www.xfront.com/owl/ontologies/camera/#Money]
[http://www.w3.org/2002/07/owl#Thing, http://www.xfront.com/owl/ontologies/camera/#PurchaseableItem, http://www.xfront.com/owl/ontologies/camera/#Camera]
[http://www.w3.org/2002/07/owl#Thing, http://www.xfront.com/owl/ontologies/camera/#PurchaseableItem, http://www.xfront.com/owl/ontologies/camera/#Lens]
[http://www.w3.org/2002/07/owl#Thing, http://www.xfront.com/owl/ontologies/camera/#PurchaseableItem, http://www.xfront.com/owl/ontologies/camera/#Body]
[http://www.w3.org/2002/07/owl#Thing, http://www.xfront.com/owl/ontologies/camera/#PurchaseableItem, http://www.xfront.com/owl/ontologies/camera/#Camera, http://www.xfront.com/owl/ontologies/camera/#Digital]
[http://www.w3.org/2002/07/owl#Thing, http://www.xfront.com/owl/ontologies/camera/#PurchaseableItem, http://www.xfront.com/owl/ontologies/camera/#Camera, http://www.xfront.com/owl/ontologies/camera/#Large-Format]