How to temporarily disable a foreign key constraint in MySQL

Question

I have two Django models, each with a ForeignKey to the other one. Deleting instances of a model returns an error because of the ForeignKey constraint:

cursor.execute("DELETE FROM myapp_item WHERE n = %s", n)
transaction.commit_unless_managed()  #a foreign key constraint fails here

cursor.execute("DELETE FROM myapp_style WHERE n = %s", n)
transaction.commit_unless_managed()

Is it possible to temporarily disable constraints in MySQL?

Answer 1

Hello @kartik,

To turn off foreign key constraint globally, do the following:

SET GLOBAL FOREIGN_KEY_CHECKS=0;

and remember to set it back when you are done

SET GLOBAL FOREIGN_KEY_CHECKS=1;

NOTE: You should only do this when you are doing single user mode maintenance. As it might resulted in data inconsistency. For example, it will be very helpful when you are uploading large amount of data using a mysqldump output

Hope it helps!!

Thank You!!