mysql 外键约束格式错误 [英] mysql Foreign key constraint is incorrectly formed error

问题描述

我有两个表，table1 是带有 ID 列的父表和带有 IDFromTable1 列的 table2>(不是实际名称)当我在 IDFromTable1 到 ID 上添加 FK 到 table1 时，我收到错误 Foreign key constraint is错误形成的错误.如果 table1 记录被删除，我想删除表 2 记录.感谢您的帮助

I have two tables, table1 is the parent table with a column ID and table2 with a column IDFromTable1 (not the actual name) when I put a FK on IDFromTable1 to ID in table1 I get the error Foreign key constraint is incorrectly formed error. I would like to delete table 2 record if table1 record gets deleted. Thanks for any help

ALTER TABLE `table2`  
   ADD CONSTRAINT `FK1` 
      FOREIGN KEY (`IDFromTable1`) REFERENCES `table1` (`ID`) 
      ON UPDATE CASCADE 
      ON DELETE CASCADE;

如果需要任何其他信息，请告诉我.我是 mysql 的新手

Let me know if any other information is needed. I am new to mysql

推荐答案

对于遇到此问题的任何人，只需运行显示引擎 INNODB 状态并查看最新外键错误部分了解详情.

For anyone facing this problem, just run SHOW ENGINE INNODB STATUS and see the LATEST FOREIGN KEY ERROR section for details.

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