MYSQL:无法添加或更新子行:外键约束失败

Question

我收到错误:

无法添加或更新子行:外键约束失败 (mydb/requests, CONSTRAINT requests_ibfk_5 FOREIGN KEY (fixture_id) REFERENCES fixtures (fix_id) ON UPDATE CASCADE ON DELETE CASCADE)

我有以下表结构:

CREATE TABLE IF NOT EXISTS `requests` (
  `request_id` int(11) unsigned NOT NULL auto_increment,
  `fixture_id` int(11) unsigned NOT NULL,
  `user_id` int(11) unsigned NOT NULL,
  `date_added` datetime NOT NULL,
  `date_modified` datetime default NULL,
  PRIMARY KEY  (`request_id`),
  UNIQUE KEY `fixture_id_2` (`fixture_id`,`user_id`),
  KEY `user_id` (`user_id`),
  KEY `date_added` (`date_added`),
  KEY `fixture_id` (`fixture_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci AUTO_INCREMENT=17 ;


CREATE TABLE IF NOT EXISTS `fixtures` (
  `id` int(11) unsigned NOT NULL auto_increment,
  `fix_id` int(11) unsigned NOT NULL default '0',
  `fixture_date` date default NULL,
  `kickoff` time default NULL,
  `venue` varchar(35) default NULL,
  `home_score` tinyint(4) default NULL,
  `away_score` tinyint(4) default NULL,
  `date_added` datetime default NULL,
  `date_modified` datetime default NULL,
  PRIMARY KEY  (`id`),
  UNIQUE KEY `fix_id` (`fix_id`),
  KEY `fixture_date` (`fixture_date`),
) ENGINE=InnoDB DEFAULT CHARSET=utf8 AUTO_INCREMENT=383 ;


ALTER TABLE `requests`
  ADD CONSTRAINT `requests_ibfk_2` FOREIGN KEY (`user_id`) REFERENCES `users` (`user_id`) ON DELETE CASCADE,
  ADD CONSTRAINT `requests_ibfk_5` FOREIGN KEY (`fixture_id`) REFERENCES `fixtures` (`fix_id`) ON DELETE CASCADE ON UPDATE CASCADE;

如果我更新父表(fixtures)的 fix_id 字段上的记录，它在子表(requests)中有一个共享 id(fixture_id)，我会收到上述错误。

我不明白为什么这个完整性约束会失败。两个表都已经具有应该级联的正确数据？

非常感谢任何帮助。

Answer 1

这都是我自己的错误。我在现实中对同一个领域有两个外国约束。我只需要脱掉一个。