查询英文的城市/州/国家摘要 [英] Query city/state/country abstracts in English

问题描述

我正在尝试从DBpedia用英语查询城市，州和国家/地区的摘要，但结果混合。

I am trying to query city, state and country abstracts in English from DBpedia with mixed results. It seems to work well with City and Country but not with State.

SELECT * WHERE {
  ?x rdfs:label "France"@en.
  ?x dbpedia-owl:abstract ?abstract.
  FILTER (LANG(?abstract) = 'en')
}

或

SELECT * WHERE {
  ?x rdfs:label "Boston"@en.
  ?x dbpedia-owl:abstract ?abstract.
  FILTER (LANG(?abstract) = 'en')
}

但是，这些查询找不到任何结果：

However, these queries don't find any results:

SELECT * WHERE {
  ?x rdfs:label "Sao Paulo"@en.
  ?x dbpedia-owl:abstract ?abstract.
  FILTER (LANG(?abstract) = 'en')
}

SELECT * WHERE {
  ?x rdfs:label "Massachusetts"@en.
  ?x dbpedia-owl:abstract ?abstract.
  FILTER (LANG(?abstract) = 'en')
}

首先，如何将搜索过滤到仅城市，州或国家/地区？其次，如何找到法国的马萨诸塞州或罗纳州？

First, how can I filter the search to only Cities, States or Countries? Second, how can I find states such as Massachusetts or Rhone in France?

推荐答案

SPARQL查询（不包括可选）仅返回可以匹配所有三重模式的结果。对于不返回结果的查询，这意味着以下有关资源？x的一个或多个语句不可用：

SPARQL queries (without OPTIONAL) only return results for which all triple patterns can be matched. For your queries that do not return results, this means one or more of the following statements about a resource ?x are not available:

• 有是 rdfs：label 圣保罗


• 标签圣保罗是带有语言标签的英语


• 有一个 rdfs：abstract


• 摘要是带有语言标签的英语

• there is a rdfs:label "Sao Paulo"
• the label "Sao Paulo" is language-tagged English
• there is an rdfs:abstract
• the abstract is language-tagged English

在此示例中，您可能想找到< http：//dbpedia.org/resource/Sao_Paulo> 。此资源的标签不是圣保罗，而是圣保罗。

In this example, you probably wanted to find <http://dbpedia.org/resource/Sao_Paulo>. The label for this resource is not "Sao Paulo", but "São Paulo".

第二个查询对我来说很有效（马萨诸塞州），但花了一些时间才能完成。

The second query worked (Massachusetts) for me, but took some time to complete.

要将结果限制为某种类型的资源（如城市，州或国家/地区），您需要指定类型。在RDF中，使用 rdf：type 指定资源的类型（或类）。您可以通过相同的方式查询该问题：

To restrict your results to resources of a certain type (like City, State or Country), you need to specify the type. In RDF, a type (or rather 'class') of a resource is specified using rdf:type. You can query that in the same way:

SELECT * WHERE {
  ?x rdfs:label "São Paulo"@en.
  ?x rdf:type dbpedia-owl:Settlement.
  ?x dbpedia-owl:abstract ?abstract.
  FILTER (LANGMATCHES(LANG(?abstract), 'en'))
}

您可以使用速记 a 代替 rdf：type ，您可以将其理解为？x 是？y。

另外， LANGMATCHES（LANG（？abstract），'en'）可能更有效评估比 LANG（？abstract）='en'）。

Instead of rdf:type you can use the shorthand a, which you can read as "?x is a ?y".
Also, LANGMATCHES(LANG(?abstract), 'en') may be more efficient to evaluate than LANG(?abstract) = 'en').

请注意，此资源 dbpedia：São_Paulo不是DBpedia中的 dbpedia-owl：City ，因为它是Wikipedia上的自治市： http://en.wikipedia.org/wiki/S%C3%A3o_Paulo 。同样， dbpedia：Massachusetts 也未定义为州。两者都是 dbpedia-owl：PopulatedPlace s。

Note that this resource dbpedia:São_Paulo is not a dbpedia-owl:City in DBpedia, because it is a municipality on Wikipedia: http://en.wikipedia.org/wiki/S%C3%A3o_Paulo. Similarly, dbpedia:Massachusetts is not defined as a state. Both are dbpedia-owl:PopulatedPlaces, though.

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