class TinyIntegerField(models.SmallIntegerField):
    def db_type(self, connection):
        if connection.settings_dict['ENGINE'] == 'django.db.backends.mysql':
            return "tinyint"
        else:
            return super(TinyIntegerField, self).db_type(connection)

class PositiveTinyIntegerField(models.PositiveSmallIntegerField):
    def db_type(self, connection):
        if connection.settings_dict['ENGINE'] == 'django.db.backends.mysql':
            return "tinyint unsigned"
        else:
            return super(PositiveTinyIntegerField, self).db_type(connection)