mysql - 包含外键约束的 Alter 语句

Question

ALTER TABLE Class_T (
ADD COLUMN 'hostId' INT,
ADD FOREIGN KEY ('hostId') REFERENCES Host_T ('hostId'));

我正在尝试在 Class_T 表中添加一列，并使其引用另一个表中的主键。我正在使用 phpmyadmin。

尝试运行此程序时，我不断收到此错误。

Error SQL query: ALTER TABLE Class_T ( ADD COLUMN 'hostId' INT, 
ADD FOREIGN KEY ('hostId')   REFERENCES Host_T ('hostId')) 
MySQL said: Documentation #1064 - 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 
'( ADD COLUMN 'hostId' INT, ADD FOREIGN KEY ('hostId') 
REFERENCES Host_T ('host' at line 1 – 

有人知道我的代码有什么问题吗？

Answer 1

尝试删除括号:

ALTER TABLE Class_T
ADD COLUMN 'hostId' INT,
ADD FOREIGN KEY ('hostId') REFERENCES Host_T ('hostId');