MySQL:无法删除/删除外键

Question

这是我迄今为止尝试过的:

mysql> alter table wp_delayedCoupons_visits remove foreign key fk_targets_visits;
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'foreign key fk_targets_visits' at line 1

mysql> alter table wp_delayedCoupons_visits drop foreign key fk_targets_visits;
ERROR 1091 (42000): Can't DROP 'fk_targets_visits'; check that column/key exists

还有反引号

mysql> alter table `wp_delayedCoupons_visits` remove foreign key `fk_targets_visits`;
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'foreign key `fk_targets_visits`' at line 1

mysql> alter table `wp_delayedCoupons_visits` drop foreign key `fk_targets_visits`;
ERROR 1091 (42000): Can't DROP 'fk_targets_visits'; check that column/key exists

mysql> show columns in wp_delayedCoupons_visits;

+-------------------+--------------+------+-----+---------+----------------+
| Field             | Type         | Null | Key | Default | Extra          |
+-------------------+--------------+------+-----+---------+----------------+
| visitId           | mediumint(5) | NO   | PRI | NULL    | auto_increment |
| visitorId         | mediumint(9) | NO   |     | NULL    |                |
| urlVisited        | varchar(500) | NO   |     | NULL    |                |
| fk_targets_visits | mediumint(5) | NO   | UNI | NULL    |                |
+-------------------+--------------+------+-----+---------+----------------+
4 rows in set (0.00 sec)

有人知道什么可能导致约束不被删除或删除吗？

Answer 1

显然，您有一个名为 fk_targets_visits 的列，但即使以 fk_ 前缀命名，也不是外键约束。

使用查找

show create table `wp_delayedCoupons_visits`

如果此表中存在外键，则通过

重新发出命令

alter table `wp_delayedCoupons_visits` drop foreign key fk_coup_visits 

假设外键名称fk_coup_visits确实存在。