在DBpedia上使用EasyRdf的Person的SPARQL查询 [英] SPARQL query of Person using EasyRdf on DBpedia

问题描述

我想从DBpedia SPARQL API获得有关人员的所有信息。
第一个问题是，请求花费了太长时间。
其次，我没有得到有关我要找的人的任何信息。
我不知道我在做什么错吗？

I want to get all information about a Person from the DBpedia SPARQL API. First problem is, the request took too long time. Second, I don't get back any information about the person I looked for. I don't know what I am doing wrong?

我的代码：

require_once "EasyRdf.php";
require_once "html_tag_helpers.php";
// Setup some additional prefixes for DBpedia
EasyRdf_Namespace::set('category', 'http://dbpedia.org/resource/Category:');
EasyRdf_Namespace::set('dbpedia', 'http://dbpedia.org/resource/');
EasyRdf_Namespace::set('dbo', 'http://dbpedia.org/ontology/');
EasyRdf_Namespace::set('dbp', 'http://dbpedia.org/property/');
$sparql = new EasyRdf_Sparql_Client('http://dbpedia.org/sparql');
$result = $sparql->query(
    'SELECT *
        WHERE {
          ?person foaf:name ?name.
          ?person foaf:name ?name.
          FILTER(regex(?person,"John Lennon"))
        }
    '
);
echo "<pre>";
print_r($result);

我的结果：

EasyRdf_Sparql_Result Object
(
    [type:EasyRdf_Sparql_Result:private] => bindings
    [boolean:EasyRdf_Sparql_Result:private] => 
    [ordered:EasyRdf_Sparql_Result:private] => 
    [distinct:EasyRdf_Sparql_Result:private] => 
    [fields:EasyRdf_Sparql_Result:private] => Array
        (
            [0] => person
            [1] => name
        )

    [storage:ArrayIterator:private] => Array
        (
        )

)

推荐答案

您不会获得类似以下结果的结果：

You're not going to get results with something like:

regex(?person,"John Lennon"

因为？person 的值是一个URI，而不是字符串，并且URI不包含空格。可以查询具有真实姓名的个人（不要忘记语言标签），如：

since the value of ?person is a URI, not a string, and URIs don't contain spaces. Instead, you could query for individuals with the actual name (don't forget the language tag), as in:

select * where {
  ?resource foaf:name "John Lennon"@en
}

SPARQL结果

我想获取所有信息

如果要获取有关某个人的所有财产价值，则可以用以下内容扩展查询：

If you want to get all the property values about a person, you could extend the query with something like:

select ?subject ?property ?object { 
  ?resource foaf:name "John Lennon"@en ;
            ?property ?object .
}

当然，这只会检索人是的数据三元组的主题，但您也可能会关心该人也是三元组的对象的事物，在这种情况下，您可能会追求：

Of course, that will only retrieve data where the person is the subject of the triples, but you might also care about things where the person is the object of a triple too, in which case you might go for:

describe ?person where {
  ?person foaf:name "John Lennon"@en
}

SPARQL结果（N-Triples）

describe 查询是依赖于实现的，但是获取资源作为主题或对象的所有三元组很普遍。

The results of describe queries are implementation dependent, but it's pretty common to get all the triples of which the resource is the subject or object.

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