刪除唯一性約束

語法如下：

alter table tableName drop index key_name;#刪除唯一性約束，實際就是刪除索引

drop index key_name on tableName; #兩種方法均可

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mysql> show create table t_user; +--------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ | Table | Create Table | +--------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ | t_user | CREATE TABLE `t_user` (`id` int(10) DEFAULT NULL,`name` varchar(32) NOT NULL,`email` varchar(128) DEFAULT NULL,UNIQUE KEY `name` (`name`,`email`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci | +--------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ 1 row in set (0.00 sec)

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mysql> alter table t_user drop index name;

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mysql> show create table t_user; +--------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ | Table | Create Table | +--------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ | t_user | CREATE TABLE `t_user` (`id` int(10) DEFAULT NULL,`name` varchar(32) NOT NULL,`email` varchar(128) DEFAULT NULL ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci | +--------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ 1 row in set (0.00 sec)

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轉載于:https://www.cnblogs.com/xiangtingshen/p/10982032.html

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