SPARQL--RDF数据的处理

深碍√TFBOYSˉ_ 2022-06-02 06:35 129阅读 0赞

上一篇文章我介绍了下RDF（**Resource Description Framework**），现在来说下怎么处理RDF。

主要使用SparQL来处理RDF，SparQL是为RDF开发的一种查询语言。SPARQL全名SPARQL Protocol and RDF Query Language

今天，先说给RDF进行简单的查找，单语句查找，举一个简单的例子：

<rdf:RDF
      xmlns:rdf='http://www.w3.org/1999/02/22-rdf-syntax-ns#'
      xmlns:vCard='http://www.w3.org/2001/vcard-rdf/3.0#'
       >
    
      <rdf:Description rdf:about="http://somewhere/JohnSmith/">
        <vCard:FN>John Smith</vCard:FN>
        <vCard:N rdf:parseType="Resource">
    	<vCard:Family>Smith</vCard:Family>
    	<vCard:Given>John</vCard:Given>
        </vCard:N>
      </rdf:Description>
    
      <rdf:Description rdf:about="http://somewhere/RebeccaSmith/">
        <vCard:FN>Becky Smith</vCard:FN>
        <vCard:N rdf:parseType="Resource">
    	<vCard:Family>Smith</vCard:Family>
    	<vCard:Given>Rebecca</vCard:Given>
        </vCard:N>
      </rdf:Description>
    
      <rdf:Description rdf:about="http://somewhere/SarahJones/">
        <vCard:FN>Sarah Jones</vCard:FN>
        <vCard:N rdf:parseType="Resource">
    	<vCard:Family>Jones</vCard:Family>
    	<vCard:Given>Sarah</vCard:Given>
        </vCard:N>
      </rdf:Description>
    
      <rdf:Description rdf:about="http://somewhere/MattJones/">
        <vCard:FN>Matt Jones</vCard:FN>
        <vCard:N
    	vCard:Family="Jones"
    	vCard:Given="Matthew"/>
      </rdf:Description>
    
    </rdf:RDF>

它的图可以表示为：

![SouthEast][]

上面的RDF可以表示为：

@prefix vCard:   <http://www.w3.org/2001/vcard-rdf/3.0#> .
    @prefix rdf:     <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
    
    <http://somewhere/MattJones/>  vCard:FN   "Matt Jones" .
    <http://somewhere/MattJones/>  vCard:N    _:b0 .
    _:b0  vCard:Family "Jones" .
    _:b0  vCard:Given  "Matthew" .
    
    
    <http://somewhere/RebeccaSmith/> vCard:FN    "Becky Smith" .
    <http://somewhere/RebeccaSmith/> vCard:N     _:b1 .
    _:b1 vCard:Family "Smith" .
    _:b1 vCard:Given  "Rebecca" .
    
    <http://somewhere/JohnSmith/>    vCard:FN    "John Smith" .
    <http://somewhere/JohnSmith/>    vCard:N     _:b2 .
    _:b2 vCard:Family "Smith" .
    _:b2 vCard:Given  "John"  .
    
    <http://somewhere/SarahJones/>   vCard:FN    "Sarah Jones" .
    <http://somewhere/SarahJones/>   vCard:N     _:b3 .
    _:b3 vCard:Family  "Jones" .
    _:b3 vCard:Given   "Sarah" .

假如使用SparQL查询FullName是John Smith的主语，语句如下：

SELECT ?x
    WHERE
     { ?x <http://www.w3.org/2001/vcard-rdf/3.0#FN> "John Smith" }

SELECT ？x  //这句代码代表了查找的东西

由于RDF文件就是主（Subject）谓（Predicate）宾（Object）

=>WHERE \{ ?x <http://www.w3.org/2001/vcard-rdf/3.0\#FN> "John Smith"\}  //?x为需要查找的东西，<http://www.w3.org/2001/vcard-rdf/3.0\#FN>为Predicate，John Smith为宾语。

得到的结果：

---------------------------------
        | x                             |
        =================================
        | <http://somewhere/JohnSmith/> |
        ---------------------------------

可以将结果转化为其他格式，以后补充完整。

[SouthEast]: /images/20220602/c6f2d89a13d746858765b228c9da035d.png