<?php
class User {

    public $id;
    public $username;
    public $password;
    public $status;
    public $lang;
    public $privacy;
    public $last_login;
    public $is_admin;
    public $create_date;

    private $DB;

    public function __construct($id=0)
    {
        $this->DB = Database::getInstance(); //Database yönetim class'ın olduğunu varsayalım..
        if ($id > 0)
            $this->load($id);
    }

    public function load($id)
    {
        $id = floatval($id);
        $get = $this->DB->getRows("SELECT * FROM users WHERE id = ".$id);
        if (count($get)>0)
        {
            $find = $get[0];

            $this->id       = $find['id'];
            $this->username     = $find['username'];
            $this->password     = $find['password'];
            $this->status       = $find['status'];
            $this->is_admin     = $find['is_admin'];
            $this->lang     = $find['lang'];
            $this->privacy      = $find['privacy'];
            $this->last_login   = $find['last_login'];
            $this->create_date  = $find['create_date'];

        } else {
            return false;
        }
    }

    public function save()
    {
        if ($this->id > 0)
        {
            $sql = "UPDATE users SET ";
            $sql.= "username = '".$this->DB->clear($this->username)."', ";
            $sql.= "password = '".$this->DB->clear($this->password)."', ";
            $sql.= "status = ".floatval($this->status).", ";
            $sql.= "is_admin = ".floatval($this->is_admin).", ";
            $sql.= "lang = '".$this->DB->clear($this->lang)."', ";
            $sql.= "privacy = ".floatval($this->privacy).", ";
            $sql.= "last_login = '".$this->DB->clear($this->last_login)."', ";
            $sql.= "create_date = '".$this->DB->clearthis->create_date)."'";
            $sql.= " WHERE id = ".$this->id;

            $this->DB->query($sql);

        } else {

            $sql = "INSERT INTO users SET ";
            $sql.= "username = '".$this->DB->clear($this->username)."', ";
            $sql.= "password = '".$this->DB->clear($this->password)."', ";
            $sql.= "status = ".floatval($this->status).", ";
            $sql.= "is_admin = ".floatval($this->is_admin).", ";
            $sql.= "lang = '".$this->DB->clear($this->lang)."', ";
            $sql.= "privacy = ".floatval($this->privacy).", ";
            $sql.= "last_login = '".$this->DB->clear($this->last_login)."', ";
            $sql.= "create_date = '".$this->DB->clear($this->create_date)."'";

            $this->DB->query($sql);
            $this->load($this->DB->getLastInsertId());
        }
    }
}

//kullanımı

$user = new User;
$user->username = $_POST['username'];
$user->password = $_POST['password'];
//...
$new_user = $user->save();

//oluşan userin ID'sini almak için
echo $new_user->id;