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MySQL删除外键列_MySQL

Jun 01, 2016 pm 01:44 PM
id java

Mysql外键

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今天遇到一个要删除外键列的问题,我发现:
Sql代码 
show create table userfans; 
Java代码 
| userfans | CREATE TABLE `userfans` ( 
  `id` int(11) NOT NULL AUTO_INCREMENT, 
  `status` int(11) DEFAULT NULL, 
  `update_time` datetime DEFAULT NULL, 
  `user` int(11) DEFAULT NULL, 
  `fllower` int(11) DEFAULT NULL, 
  `follower` int(11) DEFAULT NULL, 
  PRIMARY KEY (`id`), 
  KEY 
 `FKF025E60B81E8743E 
 
` (`fllower`), 
  KEY `FKF025E60BAFF2360E` (`user`), 
  KEY `FKF025E60BC1B86A61` (`follower`), 
  CONSTRAINT 
 `FKF025E60B81E8743E 
 
` FOREIGN 
 KEY 
 (`fllower`) REFERENCES `user` (`id`), 
  CONSTRAINT `FKF025E60BAFF2360E` FOREIGN KEY (`user`) REFERENCES `user` (`id`), 
  CONSTRAINT `FKF025E60BC1B86A61` FOREIGN KEY (`follower`) REFERENCES `user` (`id`) 
) ENGINE=InnoDB AUTO_INCREMENT=3 DEFAULT CHARSET=utf8 | 
 
刚开始我想:是不是先删除KEY,再删除constraint,最后删除列?因为MySQL的外键列和Oracle不一样,MySQL的都是有KEY的;结果试了半天一直失败,最后发现,删除外键列竟然出奇的简单:
Sql代码 
alter table userfans drop foreign key FKF025E60B81E8743E 
 

显示:
Sql代码 
Query OK, 2 rows affected (0.32 sec) 
Records: 2  Duplicates: 0  Warnings: 0 
 真的是踏破铁鞋,白费功夫!

作者“绝尘”
 

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