Best way to do multiple constructors in PHP

You can't put two __construct functions with unique argument signatures in a PHP class. I'd like to do this: class Student { protected $id; protected $name; // etc. public function __construct($id){ $this->id = $id; // other members are still uninitialized } public function __construct($row_from_database){ $this->id = $row_from_database->id; $this->name = $row_from_database->name; // etc. } } What is the best way to do this in PHP?