四 图数据库的创建

1 创建一个节点 Person {name: "My Name"}

CREATE (me:Person {name: "My Name"}) return me;

CREATE (movie:Movie {title: "Mystic River", released:1993})
RETURN movie;

2修改属性

更改属性 ： movie.tagline = "We bury our sins here, Dave. We wash them clean."

MATCH (movie:Movie)
WHERE movie.title="Mystic River"
SET movie.tagline = "We bury our sins here, Dave. We wash them clean."
RETURN movie;

更改 ： movie.released = 2003

MATCH (movie:Movie)
WHERE movie.title="Mystic River"
SET movie.released = 2003
RETURN movie;


3 增加关系-边

MATCH (me:Person), (movie:Movie)
WHERE me.name="My Name" AND
movie.title="Mystic River"
CREATE (me)-[:REVIEWED {rating:80, summary:"tragic character movie"}]->(movie);
另一种写法：

MATCH (me:Person {name:"My Name"}),
(movie:Movie {title:"Mystic River"})
CREATE (me)-[:REVIEWED {rating:80, summary:"tragic character movie"}]->(movie);

4merge：若不存在这个边，则增加这条关系：

MATCH (clint:Person),(mystic:Movie)
WHERE clint.name="Clint Eastwood" AND mystic.title="Mystic River"
MERGE (clint)-[:DIRECTED]->(mystic)
RETURN clint, mystic;

复杂一点的例子：

增加认识 knows关系：一部电影的演员与演员，演员或导演，或导演与导演之间可能认识：

MATCH (a)-[:ACTED_IN|:DIRECTED]->()<-[:ACTED_IN|:DIRECTED]-(b)
WHERE NOT (a)-[:KNOWS]-(b)
MERGE (a)-[:KNOWS]->(b);

5 删除节点和边

MATCH (me:Person {name:"My Name"})
OPTIONAL MATCH (me)-[r]-()
DELETE me,r;


6 长度等级输出

MATCH (node1)-[*]-(node2)
eg。MATCH (node1)-[*1..3]-(node2) : 三个长度等级的输出

7 shortestPath函数返回路径长度短的path

MATCH p=shortestPath( (node1)-[*]-(node2) )
RETURN length(p), nodes(p)