php - private function __construct() not working when class called on another page

im using the following type of class...

class datas{


    protected $req ;
    protected $db ;


    private function __construct()
    {
        $this->db = new Database('localhost', 'user', 'pass', 'db');
        $this->db->connect(); 
    }

    public function prnt()
    {
       echo "afafa6e5f1ga56d18a1ge";
    }
}

when i try and access the class like

$y = new datas();
$y->prnt();

Call to protected data::__construct() from invalid context

when i turn it to public, it works. is there any way to make the constructor private and still have the method of call like i have. and i was thinking which one is more secure .

any insight is appreciated guys.