Insert or Update in Save() method of Datamapper

[eluser]alaminx[/eluser]
I did that way , but the country_id in city is not update. Its value is NULL.

Code:

$country=new country($country_id);
if ( $country->exists() )
{
    $city = new city();
    $city->name = 'cityname';
    $city->save();
    $country->save($city);
}