MySQL：删除一行忽略外键约束
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MySQL: delete a row ignoring foreign key constraint
提问by Xavier_Ex
so I am working on a few tables and there are some data inconsistency between them... One or two tables have a foreign key constraint on a particular table (call it table X), but that table has multiple rows with the foreign key column.
所以我正在处理几个表，它们之间存在一些数据不一致......一个或两个表在特定表上有外键约束（称为表 X），但该表有多行带有外键列.
What I want to do is to remove the duplicated rows in table X, but the foreign key constraint is preventing me from doing this. Is there a way to force delete the rows while ignoring the foreign key constraint since I know what I'm doing?
我想要做的是删除表 X 中的重复行，但外键约束阻止我这样做。有没有办法在忽略外键约束的同时强制删除行，因为我知道我在做什么？
回答by Matt Dodge
SET foreign_key_checks = 0;
SET foreign_key_checks = 0;
That will prevent MySQL from checking foreign keys. Make sure to set it back to 1 when you are done though.
这将阻止 MySQL 检查外键。但是，请确保在完成后将其设置回 1。
Also, you could always drop the foreign key and then add it later if you wanted to only affect a singular key
此外，如果您只想影响单个键，您可以随时删除外键，然后再添加它
ALTER TABLE tableName DROP FOREIGN KEY fk;
ALTER TABLE tableName DROP FOREIGN KEY fk;
