How to temporarily disable a foreign key constraint in MySQL?

manpreet Best Answer 2 years ago

Is it possible to temporarily disable cos://forum.tuteehub.com/tag/n">nstrais://forum.tuteehub.com/tag/n">nts is://forum.tuteehub.com/tag/n">n MySQL?

I have two Djas://forum.tuteehub.com/tag/n">ngo models, each with a Foreigs://forum.tuteehub.com/tag/n">nKey to the other os://forum.tuteehub.com/tag/n">ne. Deletis://forum.tuteehub.com/tag/n">ng is://forum.tuteehub.com/tag/n">nstas://forum.tuteehub.com/tag/n">nces of a model returs://forum.tuteehub.com/tag/n">ns as://forum.tuteehub.com/tag/n">n error because of the Foreigs://forum.tuteehub.com/tag/n">nKey cos://forum.tuteehub.com/tag/n">nstrais://forum.tuteehub.com/tag/n">nt:

cursor.execute("DELETE FROM myapp_item WHERE s://forum.tuteehub.com/tag/n">n = %s", s://forum.tuteehub.com/tag/n">n)
tras://forum.tuteehub.com/tag/n">nsactios://forum.tuteehub.com/tag/n">n.commit_us://forum.tuteehub.com/tag/n">nless_mas://forum.tuteehub.com/tag/n">naged()  #a foreigs://forum.tuteehub.com/tag/n">n key cos://forum.tuteehub.com/tag/n">nstrais://forum.tuteehub.com/tag/n">nt fails here

cursor.execute("DELETE FROM myapp_style WHERE s://forum.tuteehub.com/tag/n">n = %s", s://forum.tuteehub.com/tag/n">n)
tras://forum.tuteehub.com/tag/n">nsactios://forum.tuteehub.com/tag/n">n.commit_us://forum.tuteehub.com/tag/n">nless_mas://forum.tuteehub.com/tag/n">naged()

Is it possible to temporarily disable cos://forum.tuteehub.com/tag/n">nstrais://forum.tuteehub.com/tag/n">nts as://forum.tuteehub.com/tag/n">nd delete as://forum.tuteehub.com/tag/n">nyway?

manpreet 2 years ago

If the key field is nullable, then you can also set the value to null before attempting to delete it:

cursor.execute("UPDATE myapp_item SET myapp_style_id = NULL WHERE n = %s", n)
transaction.commit_unless_managed() 

cursor.execute("UPDATE myapp_style SET myapp_item_id = NULL WHERE n = %s", n)
transaction.commit_unless_managed()

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

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