sparql查询语言学习摘要

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 ?title
WHERE
{
<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():

PREFIXdc:<http://purl.org/dc/elements/1.1/>
SELECT?title
WHERE{ ?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 Literals
4.3 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:[e-mail]> ]

4.5 三元组模型语法

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

SELECT$title
WHERE{ :book1dc:title$title }

4.6 谓-宾列表

?xfoaf:name?name ;
foaf:mbox?mbox .

4.7 宾语列表

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

4.8 复合列表

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

等价于:

?xfoaf:name?name .
?xfoaf:nick"Alice" .
?xfoaf: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

?xa:Class1 .

5. Graph Patterns (模式)
5.1 Group Graph Patterns

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

Constraints in Optional Pattern Matching

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

Multiple Optional Graph Patterns

SELECT ?name ?mbox ?hpage
WHERE{ ?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 ?y
WHERE{ { ?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 ?name
WHERE { ?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?name
WHERE{ ?x foaf:name ?name }
ORDER BY ?name
LIMIT5
OFFSET10

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 Evaluation
A B A || B A && B
T T T T
T F T F
F T T F
F F F F
T E T E
E T T E
F E E F
E F E F
E E E E
12. SPARQL定义 Definition of SPARQL
RDF 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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