删除主键 - 外键约束未正确形成
我似乎无法在表中删除主键。 所有参考文献（FKS）已被删除，但仍然不允许我删除它。
我要做的是：删除添加新键的旧主键 - 但请保留旧的列和数据（只需删除PK属性）即可。
有什么问题？
表：
CREATE TABLE `employee` (
`User` int(10) unsigned NOT NULL,
`Company` int(10) unsigned NOT NULL,
--unrelated boolean fields
PRIMARY KEY (`User`,`Company`),
KEY `FK_Employee_Company_idx` (`Company`),
CONSTRAINT `FK_Employee_Company` FOREIGN KEY (`Company`) REFERENCES `company` (`ID`) ON DELETE NO ACTION ON UPDATE NO ACTION,
CONSTRAINT `FK_Employee_User` FOREIGN KEY (`User`) REFERENCES `user` (`ID`) ON DELETE NO ACTION ON UPDATE NO ACTION
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
尝试删除：
alter table Employee
drop primary key;
问题：
错误1025：'。\ db_name＃sql-3640_4'to'。 /code>。<代码>员工删除主键
没有任何引用此表的引用。我还通过语句检查，这些语句从Information_schema.key_column_usage中选择，但不会产生任何结果。
浪费了Google上的最后几个小时，但似乎无法弄清楚。
，如果这样可以添加新列：
alter table Employee
add column ID int unsigned not null auto_increment primary key;
I cannot seem to be able to delete primary keys in a table.
All references (FKs) have been removed but it still doesn't let me delete it.
What I'm trying to do is: delete old primary keys to add a new one - but keep the old columns and data (just remove the PK attribute).
What is wrong ?
Table:
CREATE TABLE `employee` (
`User` int(10) unsigned NOT NULL,
`Company` int(10) unsigned NOT NULL,
--unrelated boolean fields
PRIMARY KEY (`User`,`Company`),
KEY `FK_Employee_Company_idx` (`Company`),
CONSTRAINT `FK_Employee_Company` FOREIGN KEY (`Company`) REFERENCES `company` (`ID`) ON DELETE NO ACTION ON UPDATE NO ACTION,
CONSTRAINT `FK_Employee_User` FOREIGN KEY (`User`) REFERENCES `user` (`ID`) ON DELETE NO ACTION ON UPDATE NO ACTION
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
Trying to delete:
alter table Employee
drop primary key;
Issue:
Error 1025: Error on rename of '.\DB_NAME#sql-3640_4' to '.\DB_NAME\employee' (errno: 150 "Foreign key constraint is incorrectly formed") SQL Statement: ALTER TABLE
DB_NAME.employeeDROP PRIMARY KEY
Nothing references this table anymore. I also checked via statements which select from information_schema.key_column_usage but yields no results.
Wasted the last hours on Google but can't seem to figure it out.
And if that would work, adding a new column:
alter table Employee
add column ID int unsigned not null auto_increment primary key;
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现有FK约束仍然需要索引。
添加以下索引（第一个）应满足该要求：
The index is still needed for the existing FK constraints.
Adding the following index (first) should satisfy that requirement:
Test case