MySQL:添加约束给出:ERROR 1452(23000):无法添加或更新子行？

Question

我有以下内容:

mysql> show create table rc_profile_table \G;
*************************** 1. row ***************************
Table: rc_profile_table
Create Table: CREATE TABLE `rc_profile_table` (
`id` int(11) NOT NULL auto_increment,
`created_at` datetime default NULL,
`name` varchar(32) NOT NULL,
`surname` varchar(32) NOT NULL,
`password` varchar(128) NOT NULL,
`unique_code` varchar(16) NOT NULL,
`msisdn` varchar(32) NOT NULL,
`current_location` varchar(64) NOT NULL,
`profile_pic` varchar(255) default NULL,
`email` varchar(128) NOT NULL,
`age` int(11) NOT NULL,
`city_of_birth` varchar(64) NOT NULL,
`personality` varchar(128) NOT NULL,
`country_id` int(11) NOT NULL,
`religious_id` int(11) NOT NULL,
`relationship_id` int(11) NOT NULL,
`wants_and_needs` varchar(512) default NULL,
`hopes_and_aspirations` varchar(512) default NULL,
`profession` varchar(128) default NULL,
`hobbies_and_interests` varchar(512) default NULL,
`skills_and_talents` varchar(512) default NULL,
`open_comment` varchar(512) default NULL,
`food_and_drinks` varchar(512) default NULL,
`activated` int(11) default NULL,
`mood_updated_at` datetime default NULL,
`mood_color` varchar(32) default NULL,
`mood_desc` varchar(64) default NULL,
`login_count` int(10) unsigned default '0',
`campus_id` int(11) default NULL,
PRIMARY KEY  (`id`),
KEY `rc_profile_table_FI_2` (`country_id`),
KEY `rc_profile_table_FI_3` (`religious_id`),
KEY `rc_profile_table_FI_4` (`relationship_id`),
KEY `rc_profile_table_FI_5` (`campus_id`),
CONSTRAINT `rc_profile_table_FK_2` FOREIGN KEY (`country_id`) REFERENCES `rc_country_table` (`id`) ON DELETE CASCADE,
CONSTRAINT `rc_profile_table_FK_3` FOREIGN KEY (`religious_id`) REFERENCES `rc_religious_type_table` (`id`) ON DELETE CASCADE,
CONSTRAINT `rc_profile_table_FK_4` FOREIGN KEY (`relationship_id`) REFERENCES `rc_relationship_type_table` (`id`) ON DELETE CASCADE,
CONSTRAINT `rc_profile_table_FK_5` FOREIGN KEY (`campus_id`) REFERENCES `rc_campus_table` (`id`) ON DELETE CASCADE
)   
ENGINE=InnoDB AUTO_INCREMENT=159 DEFAULT CHARSET=utf8
1 row in set (0.01 sec)

并且:

mysql> show create table rc_sent_items_table \G;
*************************** 1. row ***************************
Table: rc_sent_items_table
Create Table: CREATE TABLE `rc_sent_items_table` (
`profile_id_from` int(11) NOT NULL,
`profile_id_to` int(11) NOT NULL,
`message` varchar(512) default NULL,
`subject` varchar(255) default NULL,
`opened_once` int(11) default NULL,
`message_type_id` int(11) default NULL,
`id` int(11) NOT NULL auto_increment,
`created_at` datetime default NULL,
PRIMARY KEY  (`id`),
KEY `rc_sent_items_table_FI_1` (`profile_id_from`),
KEY `rc_sent_items_table_FI_2` (`profile_id_to`),
KEY `rc_sent_items_table_FI_3` (`message_type_id`),
CONSTRAINT `rc_sent_items_table_FK_3` FOREIGN KEY (`message_type_id`) REFERENCES `rc_message_type_table` (`id`) ON DELETE CASCADE
)  
ENGINE=InnoDB AUTO_INCREMENT=159 DEFAULT CHARSET=utf8
1 row in set (0.00 sec)

所以当我尝试做的时候:

ALTER TABLE rc_sent_items_table ADD CONSTRAINT `rc_sent_items_table_FK_1`
FOREIGN  KEY (`profile_id_to`) REFERENCES `rc_profile_table` (`id`) ON DELETE CASCADE;

我收到此错误:

ERROR 1452 (23000): Cannot add or update a child row: a foreign key constraint fails
(`traffic2/#sql-1122_5cf`, CONSTRAINT `rc_sent_items_table_FK_1` FOREIGN KEY
(`profile_id_to`) REFERENCES `rc_profile_table` (`id`) ON DELETE CASCADE)

我做错了什么？谢谢

Answer 1

什么地方出了错？

您要求mysql强制执行之前未发现的两个表之间的关系.不幸的是,这两个表的状态表明关系已经破裂.那只是运气不好.现在,您在rc_sent_items_table中有一些记录,其中profile_ids在rc_profile_table中不存在.

现在我该怎么做

您只需要确定rc_sent_items_table中的记录是否有效,或者您是否应该删除它们.这是一个只有你能做的电话.很可能你需要它们,然后必须将相应的记录添加到rc_profile_table.

我需要修复哪些记录？

你可以找到哪些记录不能应用约束,即你需要通过运行这样的东西来修复...

select * from rc_sent_items_table 
where profile_id not in (select profile_id from rc_profile_table)

这将使用它引用的表交叉检查'broken'表中的message_type_id.

使用innodb状态

你也可以通过检查innodb的想法得到一些有用的指示.如果在运行命令时使用'\ G'标志,您应该得到类似下面示例的内容,并在早期列出一些警告.

mysql> show innodb status \G
*************************** 1. row ***************************
  Type: InnoDB
  Name: 
Status: 
=====================================
110627 16:06:50 INNODB MONITOR OUTPUT
=====================================
Per second averages calculated from the last 11 seconds
----------
SEMAPHORES
----------
OS WAIT ARRAY INFO: reservation count 5, signal count 5
Mutex spin waits 0, rounds 0, OS waits 0
RW-shared spins 4, OS waits 2; RW-excl spins 4, OS waits 3
------------
TRANSACTIONS
------------
Trx id counter 0 167168
Purge done for trx's n:o < 0 166758 undo n:o < 0 0
History list length 13
LIST OF TRANSACTIONS FOR EACH SESSION:
---TRANSACTION 0 0, not started, process no 996, OS thread id 3013684080
MySQL thread id 34, query id 99 localhost root
show innodb status