在 Sparql WHERE 子句中使用名称空间前缀时处理逗号

Question

我正在尝试在 skos:broader 属性中查询 DBPedia 类别 "Diseases_of_oral_cavity,_salivary_glands_and_jaws"。此类别在以下 URI 中可用： http://dbpedia.org/resource/Category:Diseases_of_oral_cavity,_salivary_glands_and_jaws

以下查询提供了所需的输出：

PREFIX skos: <http://www.w3.org/2004/02/skos/core#> 

SELECT ?broaderCategory
WHERE {
    <http://dbpedia.org/resource/Category:Diseases_of_oral_cavity,_salivary_glands_and_jaws> skos:broader ?broaderCategory
}

要求是使用 Python 代码和 Sparql 包装器查询 skos:broader 属性的几个类别。我试图通过为所有 DBPedia 类别 URI 定义 PREFIX 并在 WHERE 子句中使用它来使代码更具可读性，如下所示：

PREFIX dbpcat: <http://dbpedia.org/resource/Category:> 
PREFIX skos: <http://www.w3.org/2004/02/skos/core#> 

SELECT ?broaderCategory
WHERE {
    dbpcat:Diseases_of_oral_cavity,_salivary_glands_and_jaws skos:broader ?broaderCategory
}

第二个查询 returns 类别名称中“,”处的语法错误。用转义序列（hex-unicode 和 html）替换逗号没有帮助。而且，使用字符串文字（dbc:"[category]" 和 dbc:'''[category]'''）也不是正确的语法。

在这种情况下应该如何处理逗号？

Answer 1

此答案基于 W3C recommendation for Turtle:

前缀 IRI 的本地部分不允许使用某些特殊字符。根据 section about IRIs

Prefixed names are a superset of XML QNames. They differ in that the local part of prefixed names may include:

leading digits, e.g. leg:3032571 or isbn13:9780136019701

non leading colons, e.g. og:video:height

reserved character escape sequences, e.g. wgs:lat\-long

此外，关于escape sequences的部分给了我们更多的见解：

%-encoded sequences are in the character range for IRIs and are explicitly allowed in local names. These appear as a '%' followed by two hex characters and represent that same sequence of three characters. These sequences are not decoded during processing. A term written as http://a.example/%66oo-bar in Turtle designates the IRI http://a.example/%66oo-bar and not IRI http://a.example/foo-bar. A term written as ex:%66oo-bar with a prefix @prefix ex: <http://a.example/> also designates the IRI http://a.example/%66oo-bar.

更新（根据下方评论）

正如@AndyS 指出的那样，

reserved character escape sequences consist of a '\' followed by one of ~.-!$&'()*+,;=/?#@%_ and represent the character to the right of the '\'.

所以用 \ 转义适用于逗号，即你可以写 \,。不幸的是，这在 Virtuoso Web UI 和

中仍然失败

Virtuoso 37000 Error SP030: SPARQL compiler, line 0: Bad character '\' (0x5c) in SPARQL expression at '\'

所以这应该是一个错误。

在 Sparql WHERE 子句中使用名称空间前缀时处理逗号

Handling commas when using a namespace PREFIX in a Sparql WHERE clause

semantic-web

sparql

dbpedia

virtuoso

更新（根据下方评论）