Question

我目前正在尝试为我必须提供的用例创建dbpedia数据的示例。我的主要目标是为每位欧洲艺术家要求5幅画作（我想在开始时每个国家只展示两位艺术家）。

没有限制的查询如下。

    PREFIX dbpedia-owl:<http://dbpedia.org/ontology/>
    PREFIX category: <http://dbpedia.org/resource/Category:>
    PREFIX dcterms:<http://purl.org/dc/terms/>
    PREFIX prop:<http://dbpedia.org/property/>
    PREFIX geonames:<http://sws.geonames.org/>
    PREFIX rdfs:<http://www.w3.org/2000/01/rdf-schema#>
    PREFIX dbpedia:<http://dbpedia.org/resource/>
    PREFIX geo-ont:<http://www.geonames.org/ontology#>
    PREFIX ourvocab:<http://example.org/>
    prefix foaf:<http://xmlns.com/foaf/0.1/>

    SELECT DISTINCT ?painting_name ?artist_name ?european_country ?description ?artist_birthday_year
    WHERE {

    ?european_country dcterms:subject category:Countries_in_Europe.
    ?european_country rdf:type dbpedia-owl:Place.

    ?painting prop:artist ?artist.
    ?painting rdfs:label ?painting_name.
    ?painting prop:type dbpedia:Oil_painting.
    ?painting rdfs:comment ?description.

    ?artist foaf:name ?artist_name.
    ?artist rdf:type dbpedia-owl:Artist.
    ?artist prop:placeOfBirth ?european_country.
    ?artist dbpedia-owl:birthDate ?artist_birthday.


     FILTER (lang(?painting_name) = "" || lang(?painting_name) = "en")
     FILTER (lang(?description) = "" || lang(?description) = "en")
     BIND(year(?artist_birthday) AS ?artist_birthday_year)

    }

您可以在此处运行查询：http://dbpedia.org/sparql 现在，我被卡住了，因为我不知道如何在我的用例中应用嵌套限制。非常感谢你。

带有限制的sparql中的嵌套查询

0 个答案: