zorainc

class BigForeignKey(models.ForeignKey):
    def db_type(self, connection):
        """ Adds support for foreign keys to big integers as primary keys.
        """
        rel_field = self.rel.get_related_field()
        if (isinstance(rel_field, BigAutoField) or
                (not connection.features.related_fields_match_type and
                isinstance(rel_field, (BigIntegerField, )))):