Neo4j入门（一）节点、关系的增删改查

实现效果图

 

 在上述你的例子中，一共有两类节点：City和Company，一类关系：(Company)-[belongTo]->(City)。

ADD

City的节点可以通过使用如下命令创建：

create (city: City{name: "上海市", area: "6340.5平方千米", population: "2487.09万人", alias: ["沪", "申"]});
create (city: City{name: "北京市", area: "16410平方千米", population: "2189.31万人", alias: ["京", "帝都"]});
create (city: City{name: "深圳市", area: "1997.49平方千米", population: "1756万人", alias: ["深", "鹏城"]});
create (city: City{name: "杭州市", area: "16850平方千米", population: "1193万人", alias: ["杭"]});

在上述语句中，create表示新建，小括号内是节点信息，节点的类型（label）是City，city是其别名，花括号内是该节点的属性，共有name、area、population、alias四个属性。

Company的节点可以通过使用如下命令创建：

create (company: Company{name: "阿里"});
create (company: Company{name: "网易"});
create (company: Company{name: "百度"});
create (company: Company{name: "字节跳动"});
create (company: Company{name: "新浪"});
create (company: Company{name: "拼多多"});
create (company: Company{name: "B站"});
create (company: Company{name: "小红书"});
create (company: Company{name: "华为"});
create (company: Company{name: "腾讯"});
create (company: Company{name: "招商银行"});

创建关系的命令如下：

match (city: City{name: "杭州市"}), (company: Company{name: "阿里"}) create (company) -[r:belongTo{name: "所在城市"}]-> (city);
match (city: City{name: "杭州市"}), (company: Company{name: "网易"}) create (company) -[r:belongTo{name: "所在城市"}]-> (city);
match (city: City{name: "上海市"}), (company: Company{name: "拼多多"}) create (company) -[r:belongTo{name: "所在城市"}]-> (city);
match (city: City{name: "上海市"}), (company: Company{name: "B站"}) create (company) -[r:belongTo{name: "所在城市"}]-> (city);
match (city: City{name: "上海市"}), (company: Company{name: "小红书"}) create (company) -[r:belongTo{name: "所在城市"}]-> (city);
match (city: City{name: "北京市"}), (company: Company{name: "新浪"}) create (company) -[r:belongTo{name: "所在城市"}]-> (city);
match (city: City{name: "北京市"}), (company: Company{name: "百度"}) create (company) -[r:belongTo{name: "所在城市"}]-> (city);
match (city: City{name: "北京市"}), (company: Company{name: "字节跳动"}) create (company) -[r:belongTo{name: "所在城市"}]-> (city);
match (city: City{name: "深圳市"}), (company: Company{name: "华为"}) create (company) -[r:belongTo{name: "所在城市"}]-> (city);
match (city: City{name: "深圳市"}), (company: Company{name: "腾讯"}) create (company) -[r:belongTo{name: "所在城市"}]-> (city);
match (city: City{name: "深圳市"}), (company: Company{name: "招商银行"}) create (company) -[r:belongTo{name: "所在城市"}]-> (city);

 update

如果需要更新某个节点的属性，命令如下（比如将上海市节点的简称新增“魔都”这个名字）:

MATCH (city:City)
WHERE city.name="上海市"
SET city.alias=["沪", "申", "魔都"]
RETURN city;

查看效果：

 

 select

CQL的查询语句是灵活、功能强大的。我们仅介绍简单的几个命令。

1、查询所有的节点：

查询代码：

match (n) return (n);

查询结果：

 

 2、查询所有节点的数量

查询代码：

match (n) return count(n);

查询结果：

 

 3、查询所有的Company节点

查询代码：

match (n:Company) return (n);

查询结果：