为什么此查询的第一个结果是匹配两个测试缺席,而值显示在页面上?
#Leaders of Member states of the EU for which there is no value for gender or depiction in DBpedia
SELECT DISTINCT ?leader_No_gender ?leader_No_image
WHERE {
?MS a dbo:Country; dct:subject <http://dbpedia.org/resource/Category:Member_states_of_the_European_Union>.
{?MS dbo:leader ?leader_No_gender .
FILTER NOT EXISTS {?leader_No_gender foaf:gender ?gender}
}
UNION
{?MS dbo:leader ?leader_No_image .
FILTER NOT EXISTS {?leader_No_image foaf:depiction ?image}
}
}
由@AKSW property path-based queries建议的work on the latest Virtuoso Enterprise Edition (08.03.3312
)作为主持人DBpedia-Live。 (当然,这些结果与您在静态DBpedia上找到的结果不同,仍然基于2016-10数据集,并且仍然运行在仍然存在属性路径错误的Virtuoso 07.20.3230
上。)
PREFIX dbo: <http://dbpedia.org/ontology/>
PREFIX dct: <http://purl.org/dc/terms/>
SELECT DISTINCT
?leader_No_gender
?leader_No_image
WHERE
{
?MS a dbo:Country ;
dct:subject <http://dbpedia.org/resource/Category:Member_states_of_the_European_Union> .
{ ?MS dbo:leader ?leader_No_gender .
FILTER NOT EXISTS { ?leader_No_gender dbo:wikiPageRedirects?/foaf:gender ?gender }
}
UNION
{ ?MS dbo:leader ?leader_No_image .
FILTER NOT EXISTS { ?leader_No_image dbo:wikiPageRedirects?/foaf:depiction ?image }
}
}