My SQL Workbench在SQL中添加外键时出现错误1064

Question

我想向名为"地址"；。

ALTER TABLE `students1`.`address` 
ADD CONSTRAINT `id_country`
FOREIGN KEY ()
REFERENCES `students1`.`country` ()
ON DELETE NO ACTION
ON UPDATE NO ACTION;

此请求由MySQLWorkbench自动生成。但是得到这个错误

ERROR 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 ')
REFERENCES `students1`.`country` ()
ON DELETE NO ACTION
ON UPDATE NO ACT' at line 3

如何解决此问题？

Answer 1

我不知道您的两个表是否具有相同的列id_country。

但这种情况下的语法是：

ALTER TABLE `students1`.`address` 
ADD CONSTRAINT 
FOREIGN KEY (`id_country`)
REFERENCES `students1`.`country`(`id_country`)
ON DELETE NO ACTION
ON UPDATE NO ACTION;