外键约束错误1005 erno 121

我正在努力争取创build这张桌子。 在类似的限制条件下，其他表在mariadb 10中创build得很好。 我已经通过debugging器运行它没有成功。

ERROR 1005 (HY000) at line 401 in file: '/usr/share/doc/dbmail/examples/create_tables.mysql': Can't create table `dbmail`.`dbmail_auto_replies` (errno: 121 "Duplicate key on write or update") DROP TABLE IF EXISTS `dbmail_users`; CREATE TABLE `dbmail_users` ( `user_idnr` bigint(20) UNSIGNED NOT NULL auto_increment, `userid` varchar(255) NOT NULL default '', `passwd` varchar(255) NOT NULL default '', `client_idnr` bigint(20) UNSIGNED NOT NULL default '0', `maxmail_size` bigint(20) NOT NULL default '0', `curmail_size` bigint(20) NOT NULL default '0', `maxsieve_size` bigint(20) NOT NULL default '0', `cursieve_size` bigint(20) NOT NULL default '0', `encryption_type` varchar(255) NOT NULL default '', `last_login` datetime NOT NULL default '1979-11-03 22:05:58', PRIMARY KEY (`user_idnr`), UNIQUE KEY `userid_index` (`userid`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8; DROP TABLE IF EXISTS dbmail_auto_notifications; CREATE TABLE dbmail_auto_notifications ( user_idnr bigint(20) UNSIGNED NOT NULL, notify_address varchar(100) NOT NULL default '', INDEX user_idnr_index (user_idnr), FOREIGN KEY user_idnr_fk (user_idnr) REFERENCES dbmail_users (user_idnr) ON DELETE CASCADE ON UPDATE CASCADE ) ENGINE InnoDB DEFAULT CHARSET=utf8; DROP TABLE IF EXISTS dbmail_auto_replies; CREATE TABLE dbmail_auto_replies ( user_idnr bigint(20) UNSIGNED DEFAULT '0' NOT NULL, start_date DATETIME NOT NULL, stop_date DATETIME NOT NULL, reply_body MEDIUMTEXT, INDEX user_idnr_index (user_idnr), FOREIGN KEY user_idnr_fk (user_idnr) REFERENCES dbmail_users (user_idnr) ON DELETE CASCADE ON UPDATE CASCADE ) ENGINE InnoDB DEFAULT CHARSET=utf8; 

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