[PYTHON] What is on_delete used in django's model?

About on_delete used in djnago model

Regarding the title, I have a question that I encountered while studying a book.

The actual code looked like this:


class Test_Model:
    user = models.ForeignKey(CustomUser, verbose_name='user', on_delete=models.PROTECT, null=True)

When I looked it up, it was an indispensable item when linking models from django 2.0. The meaning seems to be ** what to do with the associated object when the referenced object is deleted **.

There are the following types of model. ・ CASCADE Delete all associated objects

・ PROTECT Cannot be deleted if there is an associated object

・ SET_NULL The object remains, but the corresponding item becomes Null

・ SET_DEFAULT The object will remain and the corresponding item will have a default value.

・ SET () The object can set the function to the remaining corresponding item

・ DO_NOTHING Do nothing.

If you don't decide how to handle it properly ...

Reference site https://djangobrothers.com/blogs/on_delete/

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