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pythondjangodjango-modelsforeign-keys

How do you set the default value for Django's 'on_delete=models.SET_DEFAULT'

In the example below, how--and where--do you set the default value?

author = models.ForeignKey('Author', on_delete=models.SET_DEFAULT)

Solution

  • For SET_DEFAULT to work, default should be used in the ForeignKey declaration:

    author = models.ForeignKey('Author', on_delete=models.SET_DEFAULT, default=None, null=True)

    In this case, whatever is set as default will be used when the related object is deleted.

    EDIT: As pointed out by @MojixCoder and @Ersain, in this example you need to set null=True otherwise deleting the instance of the ForeignKey will cause IntegrityError to be raised.