Neo4J：UNIQUE约束

谁借莪１个温暖的怀抱￠ 2023-05-31 03:08 3阅读 0赞

### 1、语法说明 ###

UNIQUE 约束唯一标识数据库表中的每条记录。

CREATE CONSTRAINT ON (<label_name>)
    ASSERT <property_name> IS UNIQUE

说明：  
CONSTRAINT约束  
ASSERT 断言

### 2、示例演示 ###

CREATE CONSTRAINT ON (p:Node)
    ASSERT p.nodeId IS UNIQUE

![在这里插入图片描述][20191022160943142.png]

CREATE (p:Node{nodeId:'x001',x:1,y:1})

![在这里插入图片描述][2019102216101370.png]  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoZW5neXVxaWFuZw_size_16_color_FFFFFF_t_70]

CREATE (p:Node{nodeId:'x002',x:2,y:4})

![在这里插入图片描述][20191022161051225.png]

### 3、删除UNIQUE约束 ###

DROP CONSTRAINT ON (p:Node)
    ASSERT p.nodeId IS UNIQUE

![在这里插入图片描述][20191022161224712.png]  
再次添加相同属性的节点  
![在这里插入图片描述][20191022161332883.png]  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoZW5neXVxaWFuZw_size_16_color_FFFFFF_t_70 1]

[20191022160943142.png]: /images/20230531/4ab3a7d6ab794d6e9f6aaf93f51b9725.png
[2019102216101370.png]: /images/20230531/16386f8bce654d169b8b1ccf0d69f698.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoZW5neXVxaWFuZw_size_16_color_FFFFFF_t_70]: /images/20230531/0beee1c170da4a339c7a7b1317732144.png
[20191022161051225.png]: /images/20230531/e1243d400ee14a9d9a09b69b5d8732dd.png
[20191022161224712.png]: /images/20230531/45125a945d6a4159b737f6175504b863.png
[20191022161332883.png]: /images/20230531/e74804c84ddb4fdda16920190007e056.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoZW5neXVxaWFuZw_size_16_color_FFFFFF_t_70 1]: /images/20230531/3ca5325d63334af38a6057f743441376.png