What does "on_delete doesn't create a SQL constraint" mean?

Question

Django

Reading the Django documentation regarding model fields Link .
Regarding the on_delete argument when creating a model field, it says:

on_delete doesn't create a SQL constraint

What does this mean for a person far from databases? Does this mean that the database will eventually swell from non-deleted records?

Answer 1

It was a bit short to read the following: "Cascade deletes. Django emulates the behavior of the SQL constraint ON DELETE CASCADE and also deletes the object containing the ForeignKey."

Answer 2

To be quite blunt: the decision on what to do with the model after deleting its ForeignKey according to on_delete is made at the django level. The database does not take any part in this, it only acts as a data store.