SPARQL/前缀
< SPARQL
WDQS 理解许多快捷缩写，称为前缀。一些是 Wikidata 内部使用的，如 wd、wdt、p、ps、bd 等，还有许多其他常用的外部前缀，如 rdf、skos、owl、schema 等。
在下面的查询中，我们正在查找存在 "P279 = Q7725634" 语句的项目，或者更准确地说，选择具有 "子类" 属性和 "文学作品" 对象的主体。
对于简单的 WDQS 三元组，项目应该以 wd: 为前缀，属性应该以 wdt: 为前缀。这仅适用于固定值 - 变量没有前缀。
PREFIX wd: <http://www.wikidata.org/entity/>
PREFIX wds: <http://www.wikidata.org/entity/statement/>
PREFIX wdv: <http://www.wikidata.org/value/>
PREFIX wdt: <http://www.wikidata.org/prop/direct/>
PREFIX wikibase: <http://wikiba.se/ontology#>
PREFIX p: <http://www.wikidata.org/prop/>
PREFIX ps: <http://www.wikidata.org/prop/statement/>
PREFIX pq: <http://www.wikidata.org/prop/qualifier/>
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
PREFIX bd: <http://www.bigdata.com/rdf#>
# The below SELECT query does the following:
# Selects all the items(?s subjects) and their descriptions(?desc)
# that have(WHERE) the statement(?s subject) has a direct property(wdt:) = P279 <subclasses of>
# with a value of entity(wd:) = Q7725634 <Literary Work>
# and Optionally return the label and description using the Wikidata label service
SELECT ?s ?desc WHERE {
?s wdt:P279 wd:Q7725634 .
OPTIONAL {
?s rdfs:label ?desc
FILTER (LANG(?desc) = "en").
}
}
不使用前缀，应该写成
# The below SELECT query does the following:
# Selects all the items(?s subjects) and their descriptions(?desc)
# that have(WHERE) the statement(?s subject) has a direct property(wdt:) = P279 <subclasses of>
# with a value of entity(wd:) = Q7725634 <Literary Work>
# and Optionally return the label and description using the Wikidata label service
SELECT ?s ?desc WHERE {
?s <http://www.wikidata.org/prop/direct/P279> <http://www.wikidata.org/entity/Q7725634> .
OPTIONAL {
?s <http://www.w3.org/2000/01/rdf-schema#label> ?desc
FILTER (LANG(?desc) = "en").
}
}
实际上，所有提到的前缀都在 Wikidata 查询服务中内置，因此可以省略它们。
# The below SELECT query does the following:
# Selects all the items(?s subjects) and their descriptions(?desc)
# that have(WHERE) the statement(?s subject) has a direct property(wdt:) = P279 <subclasses of>
# with a value of entity(wd:) = Q7725634 <Literary Work>
# and Optionally return the label and description using the Wikidata label service
SELECT ?s ?desc WHERE {
?s wdt:P279 wd:Q7725634 .
OPTIONAL {
?s rdfs:label ?desc
FILTER (LANG(?desc) = "en").
}
}
内置前缀的完整列表是
PREFIX wd: <http://www.wikidata.org/entity/>
PREFIX wds: <http://www.wikidata.org/entity/statement/>
PREFIX wdv: <http://www.wikidata.org/value/>
PREFIX wdt: <http://www.wikidata.org/prop/direct/>
PREFIX wikibase: <http://wikiba.se/ontology#>
PREFIX p: <http://www.wikidata.org/prop/>
PREFIX ps: <http://www.wikidata.org/prop/statement/>
PREFIX pq: <http://www.wikidata.org/prop/qualifier/>
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
PREFIX bd: <http://www.bigdata.com/rdf#>
PREFIX wdref: <http://www.wikidata.org/reference/>
PREFIX psv: <http://www.wikidata.org/prop/statement/value/>
PREFIX psn: <http://www.wikidata.org/prop/statement/value-normalized/>
PREFIX pqv: <http://www.wikidata.org/prop/qualifier/value/>
PREFIX pqn: <http://www.wikidata.org/prop/qualifier/value-normalized/>
PREFIX pr: <http://www.wikidata.org/prop/reference/>
PREFIX prv: <http://www.wikidata.org/prop/reference/value/>
PREFIX prn: <http://www.wikidata.org/prop/reference/value-normalized/>
PREFIX wdno: <http://www.wikidata.org/prop/novalue/>
PREFIX wdata: <http://www.wikidata.org/wiki/Special:EntityData/>
PREFIX schema: <http://schema.org/>
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
PREFIX owl: <http://www.w3.org/2002/07/owl#>
PREFIX skos: <http://www.w3.org/2004/02/skos/core#>
PREFIX xsd: <http://www.w3.org/2001/XMLSchema#>
PREFIX prov: <http://www.w3.org/ns/prov#>
PREFIX bds: <http://www.bigdata.com/rdf/search#>
PREFIX gas: <http://www.bigdata.com/rdf/gas#>
PREFIX hint: <http://www.bigdata.com/queryHints#>