MySQL(InnoDB):需要删除列,并附带外键约束和索引
这是我的桌子:MySQL(InnoDB):需要删除列,并附带外键约束和索引,mysql,innodb,mysql-error-1025,mysql-error-1091,Mysql,Innodb,Mysql Error 1025,Mysql Error 1091,这是我的桌子: CREATE TABLE `alums_alumphoto` ( `id` int(11) NOT NULL auto_increment, `alum_id` int(11) NOT NULL, `photo_id` int(11) default NULL, `media_id` int(11) default NULL, `updated` datetime NOT NULL, PRIMARY KEY (`id`),
CREATE TABLE `alums_alumphoto` (
`id` int(11) NOT NULL auto_increment,
`alum_id` int(11) NOT NULL,
`photo_id` int(11) default NULL,
`media_id` int(11) default NULL,
`updated` datetime NOT NULL,
PRIMARY KEY (`id`),
KEY `alums_alumphoto_alum_id` (`alum_id`),
KEY `alums_alumphoto_photo_id` (`photo_id`),
KEY `alums_alumphoto_media_id` (`media_id`),
CONSTRAINT `alums_alumphoto_ibfk_1` FOREIGN KEY (`media_id`) REFERENCES `media_mediaitem` (`id`),
CONSTRAINT `alum_id_refs_id_706915ea` FOREIGN KEY (`alum_id`) REFERENCES `alums_alum` (`id`),
CONSTRAINT `photo_id_refs_id_63282119` FOREIGN KEY (`photo_id`) REFERENCES `media_mediaitem` (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=63 DEFAULT CHARSET=utf8
我想删除列photo\u id
,这可能还需要删除外键约束和索引
问题是,我在尝试删除列时出错:
ERROR 1025 (HY000): Error on rename of '.\dbname\#sql-670_c5c' to '.\dbname\alums_alumphoto' (errno: 150)
错误1025(HY000):将“.\dbname\#sql-670_c5c”重命名为“.\dbname\alums_alumphoto”时出错(错误号:150)
。。。当我尝试删除索引(如上所述)时,以及当我尝试删除外键约束时:
ERROR 1091 (42000): Can't DROP 'photo_id_refs_id_63282119'; check that column/key exists)
错误1091(42000):无法删除'photo_id_refs_id_63282119';检查列/键是否存在)
我应该按什么顺序做这一切?我应该使用什么精确的命令?确定的事情是创建一个重复的表
> CREATE TABLE alums_alumphoto_new LIKE alums_alumphoto;
> ALTER TABLE .... // Drop constraint
> ALTER TABLE .... // Drop KEY
> ALTER TABLE .... // Drop the column
> INSERT INTO alums_alumphoto_new (SELECT id, alum_id, photo_id, media_id, updated FROM alums_alumphoto);
> RENAME TABLE alums_alumphoto TO alums_alumphoto_old, alums_alumphoto_new TO alums_alumphoto;
如果执行重命名表时出错,其他一些表可能具有引用此表的外键约束,在这种情况下,整个方法都很愚蠢。:) 准确地说,试试这个:
首先删除外键或约束:
ALTER TABLE `alums_alumphoto` DROP FOREIGN KEY `photo_id_refs_id_63282119`;
上一个命令删除列上的外键约束。现在可以删除列photo\u id
(MySQL在删除列时会删除索引):
在本机上,您可以将这两个操作合并为一个操作:
ALTER TABLE `alums_alumphoto`
DROP FOREIGN KEY `photo_id_refs_id_63282119` ,
DROP COLUMN `photo_id`;
尝试组合DROP KEY和DROP外键语句
ALTER TABLE `alums_alumphoto`
DROP KEY KEY `alums_alumphoto_photo_id`,
DROP FOREIGN KEY `photo_id_refs_id_63282119`;
ALTER TABLE `alums_alumphoto`
DROP COLUMN `photo_id`;
您是否尝试过在同一ALTER语句中删除列和索引?
ALTER TABLE `alums_alumphoto`
DROP KEY KEY `alums_alumphoto_photo_id`,
DROP FOREIGN KEY `photo_id_refs_id_63282119`;
ALTER TABLE `alums_alumphoto`
DROP COLUMN `photo_id`;