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【文章內容簡介】 tterns – Triple Pattern – similar to an RDF Triple (subject, predicate, object), but any ponent can be a query variable。 literal subjects are allowed – Matching a triple pattern to a graph: bindings between variables and RDF Terms Matching of Basic Graph Patterns – A Pattern Solution of Graph Pattern GP on graph G is any substitution S such that S(GP) is a subgraph of G. x v rdf:type rdf:Property rdf:type rdf:type rdf:Property SELECT ?x ?v WHERE { ?x ?x ?v } ?book dc:title ?title 第 1章 基礎知識 基本圖形模式 多重匹配 PREFIX foaf: SELECT ?name ?mbox WHERE { ?x foaf:name ?name . ?x foaf:mbox ?mbox } @prefix foaf: . _:a foaf:name Johnny Lee Outlaw . _:a foaf:mbox mailto: . _:b foaf:name Peter Goodguy . _:b foaf:mbox mailto: . name mbox Johnny Lee Outlaw mailto: Peter Goodguy mailto: Group Graph Pattern (set of graph patterns) also! 數據 Query Query Result 第 1章 基礎知識 基本圖形模式 空結點 PREFIX foaf: SELECT ?x ?name WHERE { ?x foaf:name ?name } @prefix foaf: . _:a foaf:name Alice . _:b foaf:name Bob . x name _:c “Alice“ _:d “Bob” 數據 Query Query Result 第 1章 基礎知識 圖形模式 Basic Graph Pattern – set of Triple Patterns Group Pattern a set of graph patterns must all match Value Constraints restrict RDF terms in a solution Optional Graph Patterns . additional patterns may extend the solution Alternative Graph Pattern – two or more possible patterns are tried Patterns on Named Graphs patterns are matched against named graphs 第 1章 基礎知識 組模式 PREFIX foaf: SELECT ?name ?mbox WHERE { ?x foaf:name ?name . ?x foaf:mbox ?mbox } PREFIX foaf: SELECT ?name ?mbox WHERE { {?x foaf:name ?name。 foaf:mbox ?mbox } } 第 1章 基礎知識 值限制 PREFIX dc: PREFIX ns: SELECT ?title ?price WHERE { ?x ns:price ?price . FILTER ?price 30 . ?x dc:title ?title . } @prefix dc: . @prefix : . @prefix ns: . :book1 dc:title SPARQL Tutorial . :book1 ns:price 42 . :book2 dc:title The Semantic Web . :book2 ns:price 23 . title price The Semantic Web 23 Data Query Query Result 第 1章 基礎知識 53 能夠使用正規表達式 PREFIX dc: PREFIX ldap: PREFIX foaf: SELECT ?name ?name2 { ?doc dc:title ?title . FILTER regex(?title, “SPARQL”) . ?doc dc:creator ?reseacher . ?researcher ldap: ? . ?researcher ldap:name ?name } ? “Find the name and addresses of authors of a paper about SPARQL” 第 1章 基礎知識 可選圖形模式 PREFIX dc: PREFIX ns: SELECT ?title ?price WHERE { ?x dc:title ?title . OPTIONAL { ?x ns:price ?price . FILTER ?price 30 }} @prefix dc: . @prefix : . @prefix ns: . :book1 dc:title SPARQL Tutorial . :book1 ns:price 42 . :book2 dc:title The Semantic Web . :book2 ns:price 23 . title price “SPARQL Tutorial“ The Semantic Web 23 Data Query Query Result 第 1章 基礎知識 多重選擇塊 PREFIX foaf: SELECT ?name ?mbox ?hpage WHERE { ?x foaf:name ?name . OPTIONAL { ?x foaf:mbox ?mbox }. OPTIONAL { ?x foaf:homepage ?hpage } } @prefix foaf: . @prefix rdf: . @prefix rdfs: . _:a foaf:name Alice . _:a foaf:homepage . _:b foaf:name Bob . _:b foaf:mbox mailto: . Data Query Query Result name Mbox hpage “Alice“ “Bob“ mailto: 第 1章 基礎知識 可選圖模式 PREFIX dc10: PREFIX dc11: SELECT ?x ?y WHERE { { ?book dc10:title ?x } UNION { ?book dc11:title ?y } } @prefix dc10: . @prefix dc11: . _:a dc10:title SPARQL Query Language Tutorial . _:b dc11:title SPARQL Protocol Tutorial . _:c dc10:title SPARQL . _:c dc11:title SPARQL (updated) . Data Query Query Result x y SPARQL (updated) SPARQL Protocol Tutorial SPARQL SPARQL Query Language Tutorial 第 1章 基礎知識 RDF 數據集 RDF data stores may hold multiple RDF graphs: – record information about each graph – queries that involve information from more than one graph – RDF Dataset in SPARQL terminology – the background graph, which does not have a name, and zero or more named graphs, identified by URI reference the relationship between named and background graphs: – (i) to have information in the background graph that includes provenance information about the named graphs (the application is not directly trusting the information in the named graphs ) – (ii) to include the information in the named graphs in the background graph as well. 第 1章 基礎知識 RDF數據集 命名圖和背景圖的關系 Background graph @prefix dc: . dc:publisher Bob . dc:publisher Alice . Graph: @prefix foaf: . _:a foaf:name Bob . _:a foaf:mbox mailto: . Graph: @prefix foaf: . _:a foaf:name Alice . _:a foaf:mbox mailto: . 第 1章 基礎知識 RDF數據集 命名圖和背景圖的關系 Background graph @prefix foaf: . _:x foaf:name Bob . _:x foaf:mbox mailto: . _:y foaf:name Alice . _:y foaf:mbox mailto: . Graph: @prefix foaf: . _:a foaf:name Bob . _:a foaf:mbox mailto: . Graph: @prefix foaf: . _:a foaf:name Alice . _:a foaf:mbox mailto: . 第 1章 基礎知識 查詢數據集 Graph: @prefix foaf: . @prefix rdf: . @prefix rdfs: . _:a foaf:name Alice . _:a foaf:mbox mailto: . _:a foaf:knows _:b . _:b rdfs:seeAlso . rdf:type foaf:PersonalProfileDocument . _:b foaf:name Bob . _:b foaf:mbox mailto: . _:b foaf:age 32 . Graph: @prefix foaf: . @prefix rdf: . @prefix rdfs: . _:1 foaf:mbox mailto: . _:1 rdfs:seeAlso . _:1 foaf:age 35 . rdf:type fo