MySql复合外键引用同一列

Question

我正在尝试在 MySQL 中创建一个复合外键，但是两个字段都引用另一个表中的同一列。我不确定这是否是准确的方法，因为 sql 没有执行。下面是SQL语句

SQL

ALTER TABLE tableA ADD CONSTRAINT `comp_fk`
    FOREIGN KEY (`a_id` , `b_id` )
    REFERENCES `tabelB` (`p_id` , `p_id` )
    ON DELETE NO ACTION
    ON UPDATE NO ACTION;

错误

MySQL Database Error: Can't create table 'sep.#sql-984_8' (errno: 150)

Answer 1

通过单独应用约束来尝试此操作

ALTER TABLE `comp_fk`  
  ADD CONSTRAINT `test` FOREIGN KEY (`a_id`) REFERENCES `tabelB`(`id`) ON UPDATE NO ACTION ON DELETE NO ACTION,
  ADD CONSTRAINT `test2` FOREIGN KEY (`b_id`) REFERENCES `tabelB`(`id`) ON UPDATE NO ACTION ON DELETE NO ACTION