操作图数据库的语言--Cypher

本章节主要说下Cypher的基本操作:
官方文档：https://neo4j.com/docs/cypher-manual/3.5/
Cypher是一种用来处理图数据库的语言，语法比较简单。

查询
查询所有点

MATCH (n) RETURN n

查询某一Label的点

MATCH (n: Orders) RETURN n

根据UserId和Label查询唯一点

MATCH (n: Orders)  WHERE uid(n) = "12345"  RETURN n

根据Id查询边

MATCH()-[r]-()  WHERE id(r) = "11111_22222"  RETURN r

查找某一个点的邻居

MATCH (a: Orders)-[r]-(b) WHERE uid(a) = "12345"  RETURN r, b

查找某一个点的邻居 (指定关系Label和邻居Label)

MATCH (a: Orders)-[r: SoldBy]-(b: Employee)  WHERE uid(a) = "12345" RETURN r, b

查找两个点之间的路径

MATCH p = (from: Customer)-[]->(to: Orders)  WHERE uid(from) = "11111" AND uid(to) = "22222" RETURN p

查找两个点之间的路径(指定路径长度范围)

MATCH p = (from: Customer)-[*1..3]->(to: Orders)WHERE uid(from) = "11111" AND uid(to) = "22222"  RETURN p

查找两个点之间的最短路径

MATCH p = shortestPath((from: Customer)-[*..5]->(to: Orders))

按业务Id查询点

MATCH n WHERE n.__id = "12345" RETURN n

按名称模糊查询点

MATCH n  WHERE n.__name =~ "(?i).*Maria.*" RETURN n

创建结点
创建点 (指定UserId)

CREATE (n: Orders {__uid: "12345"})

创建点 (指定UserId, 属性)

CREATE (n: Orders {__uid: "12345", total: 100})

更新点

MATCH (n: Orders) WHERE uid(n) = "12345" SET n.total = 100

删除点

MATCH (n: Orders)  WHERE uid(n) = "12345" DELETE n

创建边(起点与终点也一起创建)

CREATE (src: Orders)-[r: SoldBy]->(dst: Employee)

创建边 (在已有点上创建)

MATCH (src: Orders), (dst: Employee) WHERE uid(src) = "11111" AND uid(dst) = "22222" CREATE (src)-[r: SoldBy]->(dst) 

更新边

MATCH ()-[r]-()  WHERE id(r) = "11111_22222" SET r.property = 1

删除边

MATCH ()-[r]-() WHERE id(r) = "11111_22222" DELETE r

创建俩个结点并建立关系

 create(n:Orders{uid:"12356",Employeename:Tom})，  
 (m:Orders{uid:"12357",Employeename:Joe})，
 (n)-[: KNOWS]->(m)

查询俩个节点以及关系

MATCH(n:Orders)-[KNOWS]-(m:Orders) returen n,KNOWS,m

删除俩个结点以及它们的关系

MATCH (n:Orders)-[KNOWS]-(m:Orders) DELETE n,KNOWS,m