Why 'foreign key constraint fails' when foreign key exists?

Question

I have a simple query

UPDATE `t_timecard_detail` SET  `timeoff_request_id` = \'adad8e0d-c22b-41c3-a460-6cf982729299\' WHERE `id` = \'cfc7a0a1-4e03-46a4-af89-         


        

Answer 1

I think it's a bug. MySQL shouldn't allow You to add FOREIGN KEY referencing to MyISAM table from InnoDB because MyISAM engine isn't transactional, InnoDb is.

Try:
ALTER TABLE t_timeoff_request ENGINE=InnoDB;

Answer 2

Maybe the problem is in another table, if you set a constraint on the FK. Did you set up a FK option, like ON UPDATE CASCADE?

Answer 3

Foreign key constraints can't be applied to MyISAM engine.both table should use innodb engine for supporting foreign key constraints.