<?php
class db
{
    protected $username;
    protected $password;
    protected $db;
    protected $host;
    public function set_details($username, $password, $db, $host="localhost")
    {
        if(!empty($username) && if(!empty($password) && if(!empty($db)
        {
            $this->username = $username
            $this->password = $password
            $this->db = $db
        }
        else
        {
        return false;
        }
    }
}
?>