Why 'foreign key constraint fails' when foreign key exists?
问题 I have a simple query UPDATE `t_timecard_detail` SET `timeoff_request_id` = 'adad8e0d-c22b-41c3-a460-6cf982729299' WHERE `id` = 'cfc7a0a1-4e03-46a4-af89-069a0661cf55'; which gives this error ERROR 1452 (23000): Cannot add or update a child row: a foreign key constraint fails (`demo1_timeapp`.`t_timecard_detail`, CONSTRAINT `timeoff_request_id_refs_id_48fe5c4` FOREIGN KEY (`timeoff_request_id`) REFERENCES `t_timeoff_request` (`id`)) constraint is CONSTRAINT `timeoff_request_id_refs_id_48fe5c4`