Method add_field

django/db/models/options.py:340–373

(self, field, private=False)

        self._expire_cache()

    def add_field(self, field, private=False):
        # Insert the given field in the order in which it was created, using
        # the "creation_counter" attribute of the field.
        # Move many-to-many related fields from self.fields into
        # self.many_to_many.
        if private:
            self.private_fields.append(field)
        elif field.is_relation and field.many_to_many:
            bisect.insort(self.local_many_to_many, field)
        else:
            bisect.insort(self.local_fields, field)
            self.setup_pk(field)

        # If the field being added is a relation to another known field,
        # expire the cache on this field and the forward cache on the field
        # being referenced, because there will be new relationships in the
        # cache. Otherwise, expire the cache of references *to* this field.
        # The mechanism for getting at the related model is slightly odd -
        # ideally, we'd just ask for field.related_model. However,
        # related_model is a cached property, and all the models haven't been
        # loaded yet, so we need to make sure we don't cache a string
        # reference.
        if (
            field.is_relation
            and hasattr(field.remote_field, "model")
            and field.remote_field.model
        ):
            try:
                field.remote_field.model._meta._expire_cache(forward=False)
            except AttributeError:
                pass
            self._expire_cache()
        else:
            self._expire_cache(reverse=False)

    def setup_pk(self, field):
        if not self.pk and field.primary_key: