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MySQL 创建外键 报错 1452 - Cannot add or update a child row: a foreign
source link: https://segmentfault.com/a/1190000039682286
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大致报错内容
1452 - Cannot add or update a child row: a foreign key constraint fails
navicat创建外键时报错
关于navicat创建外键具体步骤，参见此文：navicat 数据表添加外键
两张表的数据不匹配（参见下图）
例子：
myorder表中userId字段是外键，关联user表中的userId字段。
myorder表中userId字段的值是0，而user表中没有userId=0的，这样就出现了数据不匹配的问题。如果ctrl+s保存myorder表就会报错。
修改myorder表中字段userId的值即可（与user表匹配）
ctrl+s，不再报错
Mysql错误1452 - Cannot add or update a child row: a foreign key constraint fails 原因及解决方法
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