Sparql Skos：Broader

Question

我正在对DBpediaset进行SPARQL查询，但是由于查询限制，我遇到了一些问题（由于缺乏详细的SPARQL知识）：

我首先“让”所有音乐艺术家：

?person rdf:type <http://dbpedia.org/ontology/MusicalArtist> .

但是我想将其限制为更广泛的类别Category:American_musicians（通过遍历skos:broader？）：如何？

* =虽然问题很具体，但是当我想运行sparql查询时，我已经多次遇到了这个问题。

Answer 1

使用SPARQL 1.1中的属性路径可以使此操作更容易

SELECT DISTINCT ( ?person )
WHERE
{
  ?person rdf:type dbpedia-owl:MusicalArtist .
  ?person skos:subject  skos:broader* category:American_musicians  .
}

在这里，它显示可以通过该skos:broader属性访问的所有祖先。

Answer 2

没有真正好的方法来做到这一点，但这里有一个详细的方法：

SELECT DISTINCT ( ?person )
WHERE
{
  ?person rdf:type dbpedia-owl:MusicalArtist .
  {
    ?person skos:subject [ skos:broader category:American_musicians ] .
  } UNION {
    ?person skos:subject [ skos:broader [ skos:broader category:American_musicians ] ] .
  } UNION {
    ?person skos:subject [ skos:broader [ skos:broader [ skos:broader category:American_musicians ] ] ] .
  } UNION {
    ?person skos:subject [ skos:broader [ skos:broader [ skos:broader [ skos:broader category:American_musicians ] ] ] ] .
  } UNION {
    ?person skos:subject [ skos:broader [ skos:broader [ skos:broader [ skos:broader [ skos:broader category:American_musicians ] ] ] ] ] .
  } UNION {
    ?person skos:subject [ skos:broader [ skos:broader [ skos:broader [ skos:broader [ skos:broader [ skos:broader category:American_musicians ] ] ] ] ] ] .
  } UNION {
    ?person skos:subject [ skos:broader [ skos:broader [ skos:broader [ skos:broader [ skos:broader [ skos:broader [ skos:broader category:American_musicians ] ] ] ] ] ] ] .
  }
}

为了确定需要多少级别，您可以将 SELECT DISTINCT 更改为 SELECT COUNT DISTINCT，并在计数停止增加时停止添加级别。