Method _test_m2m_db_constraint

tests/schema/tests.py:698–723

(self, M2MFieldClass)

        self.assertForeignKeyNotExists(BookWeak, "author_id", "schema_author")

    def _test_m2m_db_constraint(self, M2MFieldClass):
        class LocalAuthorWithM2M(Model):
            name = CharField(max_length=255)

            class Meta:
                app_label = "schema"
                apps = new_apps

        self.local_models = [LocalAuthorWithM2M]

        # Create the table
        with connection.schema_editor() as editor:
            editor.create_model(Tag)
            editor.create_model(LocalAuthorWithM2M)
        # Initial tables are there
        list(LocalAuthorWithM2M.objects.all())
        list(Tag.objects.all())
        # Make a db_constraint=False FK
        new_field = M2MFieldClass(Tag, related_name="authors", db_constraint=False)
        new_field.contribute_to_class(LocalAuthorWithM2M, "tags")
        # Add the field
        with connection.schema_editor() as editor:
            editor.add_field(LocalAuthorWithM2M, new_field)
        self.assertForeignKeyNotExists(
            new_field.remote_field.through, "tag_id", "schema_tag"
        )

    @skipUnlessDBFeature("supports_foreign_keys")
    def test_m2m_db_constraint(self):