[转】sparql查询语言学习摘要

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SPARQL Query Language for RDF

Contents

* 1. Intoduction * 2. Making Simple Queries * 3. RDF Term Constraints * 4. SPARQL Syntax (语法) o 4.1 IRIs (URIs) o 4.2 平凡文字的语法 Syntax for Literals o 4.3 查询变量的Syntax o 4.4 空白节点的语法 o 4.5 三元组模型语法 o 4.6 谓-宾列表 o 4.7 宾语列表 o 4.8 复合列表 o 4.9 RDF集合 o 4.10 当rdf:type是谓词时可用a代替 * 5. Graph Patterns (模式) o 5.1 Group Graph Patterns o 5.2 Empty Group Pattern o 5.3 Scope of Filters 过滤范围 * 6. Including Optional Values (可选值) * 7. 匹配两个中的一个 Matching Alternatives * 8. RDF Dataset 数据集合 * 9. 结果排序和修改 Solution Sequences and Modifiers o 重复结果 Duplicate Soulution * 10. 查询形式 Query Forms * 11. 测试值 Testing Values o 操作数数据类型Openrand Data Types o 过滤评价 Filter Evaluation * 12. SPARQL定义 Definition of SPARQL o RDF Terms(术语)

1. Intoduction

* Turtle data format （Tutle数据格式）

2. Making Simple Queries

简单查询:

SELECT ?titleWHERE{ <http://example.org/book/book1> <http://purl.org/dc/elements/1.1/title> ?title .}

Building RDF Graphs, 用Construct代替Select:

CONSTRUCT { ?x foaf:name ?name }WHERE { ?x org:employeeName ?name }

3. RDF Term Constraints

正则表达式过滤 FILTER regex():

PREFIX dc: <http://purl.org/dc/elements/1.1/>SELECT ?titleWHERE { ?x dc:title ?title FILTER regex(?title, "web", "i" ) }

4. SPARQL Syntax (语法)4.1 IRIs (URIs)

同一个IRI的不同表示方式:

<http://example.org/book/book1>

BASE <http://example.org/book/><book1>

PREFIX book: <http://example.org/book/>book:book1

4.2 平凡文字的语法 Syntax for Literals4.3 查询变量的Syntax

'?','$' 两者是等价的

4.4 空白节点的语法

[ :p "v" ] .[] :p "v" ._:b57 :p "v" . //前面加_:的标签[ :p "v" ] :q "w" . //空白节点的组合

简略空白节点:

[ foaf:name ?name ; foaf:mbox <mailto:alice@example.org> ]

4.5 三元组模型语法

PREFIX dc: <http://purl.org/dc/elements/1.1/>PREFIX : <http://example.org/book/>

SELECT $titleWHERE { :book1 dc:title $title }

4.6 谓-宾列表

?x foaf:name ?name ; foaf:mbox ?mbox .

4.7 宾语列表

?x foaf:nick "Alice" , "Alice_" .

4.8 复合列表

?x foaf:name ?name ; foaf:nick "Alice" , "Alice_" .

等价于:

?x foaf:name ?name .?x foaf:nick "Alice" .?x foaf:nick "Alice_" .

4.9 RDF集合

(1 ?x 3 4) :p "w" .

4.10 当rdf:type是谓词时可用a代替

?x a :Class1 .

5. Graph Patterns (模式)5.1 Group Graph Patterns

PREFIX foaf: <http://xmlns.com/foaf/0.1/>SELECT ?name ?mboxWHERE { ?x foaf:name ?name . ?x foaf:mbox ?mbox . }

5.2 Empty Group Pattern

{} SELECT ?x WHERE {}

5.3 Scope of Filters 过滤范围

FILTER regex(?name, "Smith")

6. Including Optional Values (可选值)

Optional Pattern Matching

WHERE { ?x foaf:name ?name . OPTIONAL { ?x foaf:mbox ?mbox } }

Constraints in Optional Pattern Matching

SELECT ?title ?priceWHERE { ?x dc:title ?title . OPTIONAL { ?x ns:price ?price . FILTER (?price < 30) } }

Multiple Optional Graph Patterns

SELECT ?name ?mbox ?hpageWHERE { ?x foaf:name ?name . OPTIONAL { ?x foaf:mbox ?mbox } . OPTIONAL { ?x foaf:homepage ?hpage } }

7. 匹配两个中的一个 Matching Alternatives

UNION:

SELECT ?x ?yWHERE { { ?book dc10:title ?x } UNION { ?book dc11:title ?y } }

8. RDF Dataset 数据集合

查询多个Graph中的信息9. 结果排序和修改 Solution Sequences and Modifiers

排序 ORDER BY:

SELECT ?nameWHERE { ?x foaf:name ?name }ORDER BY ?name

映射 Projection重复结果 Duplicate Soulution

唯一 DISTINCT:

PREFIX foaf: <http://xmlns.com/foaf/0.1/>SELECT DISTINCT ?name WHERE { ?x foaf:name ?name }

简化 REDUCED:

PREFIX foaf: <http://xmlns.com/foaf/0.1/>SELECT REDUCED ?name WHERE { ?x foaf:name ?name }

偏移 OFFSET, 限制 LIMIT:

SELECT ?nameWHERE { ?x foaf:name ?name }ORDER BY ?nameLIMIT 5OFFSET 10

10. 查询形式 Query Forms

SELECT

Returns all, or a subset of, the variables bound in a query pattern match.

CONSTRUCT

Returns an RDF graph constructed by substituting variables in a set of triple templates.

ASK

Returns a boolean indicating whether a query pattern matches or not.

DESCRIBE

Returns an RDF graph that describes the resources found.

11. 测试值 Testing Values操作数数据类型Openrand Data Types

* xsd:integer * xsd:decimal * xsd:float * xsd:double * xsd:string * xsd:boolean * xsd:dateTime

过滤评价 Filter EvaluationA B A || B A && BT T T TT F T FF T T FF F F FT E T EE T T EF E E FE F E FE E E E12. SPARQL定义 Definition of SPARQLRDF Terms(术语)

RDF Term:

RDF Let I be the set of all IRIs. Let RDF-L be the set of all RDF Literals Let RDF-B be the set of all blank nodes in RDF graphs

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