Question

我有以下SPARQL查询，它应该检索Category：Computer_science类别和Category：German_scientists

之间的常见类别

SELECT DISTINCT ?subject WHERE {
?subject <http://purl.org/dc/terms/subject> ?cat1, ?cat2 .
?cat1 skos:broader? / skos:broader? / skos:broader?         
  <http://dbpedia.org/resource/Category:Computer_science> .     
?cat2 skos:broader? / skos:broader? / skos:broader?
  <http://dbpedia.org/resource/Category:German_scientists>.
} LIMIT 10

我需要获得最接近他们的类别或者两个类别的最短路径，我该怎么做？例如，如何在（computer_science）和（German_scientists）之间的每个常见类别之间获得长度？

Answer 1

Virtuoso，为DBpedia数据提供服务的端点支持对属性路径的非标准SPARQL扩展：而不仅仅是p*，p+和p?，表示路径为Virtuoso长度分别为“零或更多”，“一个或多个”和“零或一个”，也支持p{m,n}，意思是长度“至少为m且最多为n”的路径。通过尝试n = 0并增加m值的以下查询，我开始得到m = 4的结果：

prefix category: <http://dbpedia.org/resource/Category:>

select distinct ?super where {
  ?super (^skos:broader){0,4} category:Computer_science, category:German_scientists
}

super
-----------------------------------------------
http://dbpedia.org/resource/Category:Technology
http://dbpedia.org/resource/Category:Science

Answer 2

为澄清起见：：查询是以下答案的PREFIX版本，遵循当前规范：

PREFIX dbpedia: <http://dbpedia.org/resource/>
PREFIX dcterms: <http://purl.org/dc/terms/>
PREFIX dbc: <http://dbpedia.org/resource/Category:>
select distinct ?super where {
  ?super (^skos:broader){0,4} dbc:Computer_science, dbc:German_scientists
}

SPARQL RESULTS

super
--------------------------------------------
http://dbpedia.org/resource/Category:Science_and_technology

使用DBpedia在两个维基百科类别之间的常见超类别

2 个答案: