Question

这个想法非常简单：我有三个（或更多）表

- master_tbl (id, something, somethingelse)
- tbl2 (id, ....)
- tbl3 (id, ....)

现在我想要的是一个外键关系，比如tbl3.id会指向tbl2.id而tbl2.id会指向master_tbl.id - 所有外键都是ON UPDATE CASCADE和ON DELETE CASCADE 。我从中得到的是，当我从tbl2中删除一条记录时，它的tbl3等价物也将被删除，但不会被删除master_tbl。当我从master_tbl中删除记录时，所有三个表都将被删除。

当我尝试在tbl3.id-＆gt; tbl2.id上创建外键时，我得到mysql错误150 - 无法创建表（已经创建了tbl2.id-＆gt; master_tbl.id）。我的MySQL版本是5.1.46。任何想法为什么会这样？

编辑：表格定义 smf_members又名master_table

-- Table "smf_members" DDL

CREATE TABLE `smf_members` (
  `id_member` mediumint(8) unsigned NOT NULL AUTO_INCREMENT,
  `member_name` varchar(80) NOT NULL DEFAULT '',
  `date_registered` int(10) unsigned NOT NULL DEFAULT '0',
  `posts` mediumint(8) unsigned NOT NULL DEFAULT '0',
  `id_group` smallint(5) unsigned NOT NULL DEFAULT '0',
  `lngfile` varchar(255) NOT NULL DEFAULT '',
  `last_login` int(10) unsigned NOT NULL DEFAULT '0',
  `real_name` varchar(255) NOT NULL DEFAULT '',
  `instant_messages` smallint(5) NOT NULL DEFAULT '0',
  `unread_messages` smallint(5) NOT NULL DEFAULT '0',
  `new_pm` tinyint(3) unsigned NOT NULL DEFAULT '0',
  `buddy_list` text NOT NULL,
  `pm_ignore_list` varchar(255) NOT NULL DEFAULT '',
  `pm_prefs` mediumint(8) NOT NULL DEFAULT '0',
  `mod_prefs` varchar(20) NOT NULL DEFAULT '',
  `message_labels` text NOT NULL,
  `passwd` varchar(64) NOT NULL DEFAULT '',
  `openid_uri` text NOT NULL,
  `email_address` varchar(255) NOT NULL DEFAULT '',
  `personal_text` varchar(255) NOT NULL DEFAULT '',
  `gender` tinyint(4) unsigned NOT NULL DEFAULT '0',
  `birthdate` date NOT NULL DEFAULT '0001-01-01',
  `website_title` varchar(255) NOT NULL DEFAULT '',
  `website_url` varchar(255) NOT NULL DEFAULT '',
  `location` varchar(255) NOT NULL DEFAULT '',
  `icq` varchar(255) NOT NULL DEFAULT '',
  `aim` varchar(255) NOT NULL DEFAULT '',
  `yim` varchar(32) NOT NULL DEFAULT '',
  `msn` varchar(255) NOT NULL DEFAULT '',
  `hide_email` tinyint(4) NOT NULL DEFAULT '0',
  `show_online` tinyint(4) NOT NULL DEFAULT '1',
  `time_format` varchar(80) NOT NULL DEFAULT '',
  `signature` text NOT NULL,
  `time_offset` float NOT NULL DEFAULT '0',
  `avatar` varchar(255) NOT NULL DEFAULT '',
  `pm_email_notify` tinyint(4) NOT NULL DEFAULT '0',
  `karma_bad` smallint(5) unsigned NOT NULL DEFAULT '0',
  `karma_good` smallint(5) unsigned NOT NULL DEFAULT '0',
  `usertitle` varchar(255) NOT NULL DEFAULT '',
  `notify_announcements` tinyint(4) NOT NULL DEFAULT '1',
  `notify_regularity` tinyint(4) NOT NULL DEFAULT '1',
  `notify_send_body` tinyint(4) NOT NULL DEFAULT '0',
  `notify_types` tinyint(4) NOT NULL DEFAULT '2',
  `member_ip` varchar(255) NOT NULL DEFAULT '',
  `member_ip2` varchar(255) NOT NULL DEFAULT '',
  `secret_question` varchar(255) NOT NULL DEFAULT '',
  `secret_answer` varchar(64) NOT NULL DEFAULT '',
  `id_theme` tinyint(4) unsigned NOT NULL DEFAULT '0',
  `is_activated` tinyint(3) unsigned NOT NULL DEFAULT '1',
  `validation_code` varchar(10) NOT NULL DEFAULT '',
  `id_msg_last_visit` int(10) unsigned NOT NULL DEFAULT '0',
  `additional_groups` varchar(255) NOT NULL DEFAULT '',
  `smiley_set` varchar(48) NOT NULL DEFAULT '',
  `id_post_group` smallint(5) unsigned NOT NULL DEFAULT '0',
  `total_time_logged_in` int(10) unsigned NOT NULL DEFAULT '0',
  `password_salt` varchar(255) NOT NULL DEFAULT '',
  `ignore_boards` text NOT NULL,
  `warning` tinyint(4) NOT NULL DEFAULT '0',
  `passwd_flood` varchar(12) NOT NULL DEFAULT '',
  `pm_receive_from` tinyint(4) unsigned NOT NULL DEFAULT '1',
  PRIMARY KEY (`id_member`),
  KEY `member_name` (`member_name`),
  KEY `real_name` (`real_name`),
  KEY `date_registered` (`date_registered`),
  KEY `id_group` (`id_group`),
  KEY `birthdate` (`birthdate`),
  KEY `posts` (`posts`),
  KEY `last_login` (`last_login`),
  KEY `lngfile` (`lngfile`(30)),
  KEY `id_post_group` (`id_post_group`),
  KEY `warning` (`warning`),
  KEY `total_time_logged_in` (`total_time_logged_in`),
  KEY `id_theme` (`id_theme`)
) ENGINE=InnoDB AUTO_INCREMENT=73 DEFAULT CHARSET=utf8;

cyp_users aka tbl2

-- Table "cyp_users" DDL

CREATE TABLE `cyp_users` (
  `id` mediumint(8) unsigned NOT NULL,
  `role` varchar(255) NOT NULL DEFAULT 'unregistered',
  PRIMARY KEY (`id`),
  CONSTRAINT `cyp_users_ibfk_1` FOREIGN KEY (`id`) REFERENCES `smf_members` (`id_member`) ON DELETE CASCADE ON UPDATE CASCADE
) ENGINE=InnoDB DEFAULT CHARSET=latin1;

cyp_vip_users又名tbl3

-- Table "cyp_vip_users" DDL

CREATE TABLE `cyp_vip_users` (
  `id` mediumint(8) NOT NULL,
  `od` date NOT NULL,
  `do` date NOT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1;

Answer 1

ID's tbl2和tbl3的{{1}}种类不同外键必须属于同一类型。

tbl2.ID是UNSIGNED
tbl3.ID是SIGNED

MySQL外键到另一个外键

1 个答案: