如何在MarkLogic中处理不区分大小写的SPARQL数据 [英] How to handle case-insensitive SPARQL data in MarkLogic

问题描述

我试图了解如何最好地处理Marklogic SPARQL数据中的文字(无论如何).我希望能够进行不区分大小写的搜索，但是我相信语义查询是不可能做到的.对于一个简单的例子，我想要:

I'm trying to understand how best to handle literals in Marklogic SPARQL data which may be in any case. I'd like to be able to do a case insensitive search but I believe that isn't possible with semantic queries. For a simplistic example I want:

SELECT *
WHERE { ?s ?p "Red"}

和

SELECT *
WHERE { ?s ?p "red"}

返回所有值，无论对象是"Red"，"RED"，"red"还是"rED".

to return all values whether the object is "Red", "RED", "red" or "rED".

我的数据来自具有可变大小写规则的另一个来源.目前，我唯一想到的就是添加一个额外的三元组，该三元组始终以小写形式包含文本，以便我始终可以搜索该值.另外，是否可以使用不区分大小写的排序规则在MarkLogic中创建一些新的范围查询(如果可能在三重数据上使用)?

My data is from another source which has variable capitalisation rules. At the moment the only thing I can think of is to add an extra triple which always contains the text in lower case so I can always search on that value. Alternatively, would it make sense to create some new range query in MarkLogic with a case insensitive collation (if that's possible on triple data)?

推荐答案

您可以使用忽略大小写的过滤器.

You could use a filter that ignores case.

select * where {
  ?s ?p ?o
  FILTER (lcase(str(?o)) = "red")
}

基于以下答案另一个问题.

我向MarkLogic的PM Steve Buxton询问了语义功能，他提出了以下建议:

I asked Steve Buxton, MarkLogic's PM for semantics features, and he suggested this:

let $store := sem:store( (), cts:element-value-query(xs:QName("sem:object"), "red", "case-insensitive") )
return
  sem:sparql('
    SELECT ?o
    WHERE {
      ?s ?p ?o
      FILTER (lcase(str(?o)) = "red")
    }', (), (), $store
 )

sem:store是MarkLogic 8(现在可通过早期访问获得))功能，选择一组三元组.然后在缩减集上运行 SPARQL 查询，限制需要过滤的三元组的数量.

sem:store is a MarkLogic 8 (now available through Early Access) function that selects a group of triples. The SPARQL query then runs on the reduced set, limiting the number of triples that need to be filtered.

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