7

我希望有人可以帮助我解决这个可能完全容易解决的问题：

我想针对以下 RDF 运行 SPARQL 查询（在 N3 中注明，RDF/XMl 位于此处）。这是对期刊文章的描述以及对期刊、作者和出版商的描述：

 @prefix bibo: <http://purl.org/ontology/bibo/> .
 @prefix dc: <http://purl.org/dc/elements/1.1/> .
 @prefix ex: <http://example.org/thesis/> .
 @prefix foaf: <http://xmlns.com/foaf/0.1/> .
 @prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .

<ex:XY>     a bibo:Article;
     dc:creator ex:umstaetter;
     dc:date "2008-11-01";
     dc:isPartOf ex:bibdienst;
     dc:title "DDC in Europa"@de;
     bibo:endPage "1221";
     bibo:issue "11";
     bibo:language "de";
     bibo:pageStart "1194";
     bibo:uri <http://www.zlb.de/Erschliessung020309BD.pdf>;
     bibo:volume "42" .

<ex:bibdienst>     a bibo:Journal;
     dc:publisher ex:zlb;
     dc:title "Bibliotheksdienst"@de;
     bibo:issn "00061972" .

<ex:umstaetter>     a foaf:person;
     foaf:birthday "1941-06-12";
     foaf:gender "Male";
     foaf:givenName "Walther";
     foaf:homepage <http://www.ib.hu-berlin.de/~wumsta/index.html>;
     foaf:img "http://libreas.eu/ausgabe7/pictures/wumstaetter1.jpg";
     foaf:name "Walther Umst\u00E4tter";
     foaf:surname "Umst\u00E4tter";
     foaf:title "Prof. Dr. rer. nat." .

<ex:zlb>     a foaf:Organization;
     foaf:homepage <http://www.zlb.de>;
     foaf:name "Zentral- und Landesbibliothek Berlin"@de .

出于测试目的，我想读出 ex:zlb 的foaf : homepage - 我要运行的 SPARQL 是：

PREFIX rdf:<http://www.w3.org/1999/02/22-rdf-syntax-ns#>
PREFIX dc: <http://purl.org/dc/elements/1.1/>
PREFIX bibo: <http://purl.org/ontology/bibo/>
PREFIX foaf: <http://xmlns.com/foaf/0.1/>
PREFIX ex: <http://example.org/thesis/>

SELECT ?article ?publisher ?publisher_url
WHERE 
{
    ?article dc:isPartOf ?journal .
    ?journal dc:publisher ?publisher .
    ?publisher foaf:homepage ?publisher_url
}

（再次重申：这将仅用于测试，因为文章只有一个实体。）

用 Python 和 RDflib 在我的本地机器上运行它并没有给我结果。Online Redland SPARQL 查询演示也没有。

有人看到解决方案吗？我是在正确的道路上还是完全错误的？

4

2 回答 2

7

I don't think that you can use a QName in an XML attribute value; e.g. the value of rdf:about. So consider this line from your RDF/XML file:

 <bibo:Journal rdf:about="ex:bibdienst">

I think that this is actually saying that the subject URI is "ex:bibdienst". That is a syntactically valid URI, but it is not the same URI as appears as the object of the triple corresponding to this line:

 <dc:isPartOf rdf:resource="http://example.org/thesis/bibdienst" />

Try replacing the QNames in XML attribute values with the corresponding URIs and see if that fixes your problem.

于 2009-10-20T14:22:28.360 回答
6

是的，Stephen C 完全正确，您不能在 XML 属性中使用 QNames，您可以使用 XML 实体，而不是在文档顶部的 DTD 块中定义，如下所示：

例如。

<!DOCTYPE rdf:RDF[
    <!ENTITY rdf 'http://www.w3.org/1999/02/22-rdf-syntax-ns#'>
    <!ENTITY rdfs 'http://www.w3.org/2000/01/rdf-schema#'>
    <!ENTITY xsd 'http://www.w3.org/2001/XMLSchema#'>
    <!ENTITY ex 'http://example.org/thesis/'>
    <!ENTITY dc 'http://purl.org/dc/elements/1.1/'>
    <!ENTITY foaf 'http://xmlns.com/foaf/0.1/'>
    <!ENTITY bibo 'http://purl.org/ontology/bibo/'>
]>

然后你可以像这样定义属性：

<bibo:Journal rdf:about="&ex;bibdienst">
于 2009-10-20T14:55:57.730 回答