def dbStore(self, typ, py_value):
        """
        Prepares to store this column for the a particular backend database.

        :param backend: <orb.Database>
        :param py_value: <variant>
        :param context: <orb.Context>

        :return: <variant>
        """
        # convert base types to work in the database
        if isinstance(py_value, (list, tuple, set)):
            py_value = tuple((self.dbStore(x) for x in py_value))
        elif isinstance(py_value, orb.Collection):
            py_value = py_value.ids()
        elif isinstance(py_value, orb.Model):
            py_value = py_value.id()

        return py_value