class Dining_Room_DB_Mapper extends DB_Property_Object {
 
 function __construct($init_id = 0) {
  $this->model = new Dining_Room_Model();
  $this->id = $init_id;
  $this->db_table_name = 'dinning_room';
  $this->db_key = 'object';
  $this->populate();
 }
 
 
 
}

 
<?php 
/**
 * Dining Room Model and Datastore layer
 * @author nicholasdunbar
 *
 */
define('DB_NAME','test');
define('DB_USER', 'root');
define('DB_PASS', '');
//Requires PHP 5.3.0 or greater
if (!defined('PHP_VERSION_ID')) {
 $version = explode('.', PHP_VERSION);
 define('PHP_VERSION_ID', ($version[0] * 10000 + $version[1] * 100 + $version[2]));
}
//Check Version Number
if (PHP_VERSION_ID < 50300){
 exit();
}
/**
 * This class detects when a model changes and automatically backs it up to the database
 * @author nicholasdunbar
 *
 */
abstract class DB_Property_Object
{
 //Database link - it is static so that all DB_Property_Objects have access to it and it only has to be instantiated once.
 private static $database;
 //What ever model you want to save to the database, the model should be a flat class
 protected $model;
 //The name of the table where you intend to save the model
 protected $db_table_name;
 //the name of the field where you intend to save the model, it should be a binnary blob and each record should have an auto incementing id called 'id'
 protected $db_key;
 //the id of the saved model
 protected $id;
 
 
 public function __get($name)
 {
 if (isset($this->model) && property_exists($this->model, $name))
 {
 return $this->model->$name;
 } else {
 echo 'Cannot get: Does not contain property '.$name;
 }
 return NULL;
 }
 /**
  * Make sure that when any private accessors are changed that 
  * the object is backed up to the database
  * @param string $name
  * @param string $value
  */
 public function __set($name, $value)
 {
 $isChanged = FALSE;
 $serializedObj = NULL;
 $this->connect();
 if (isset($this->model) && property_exists($this->model, $name))
 {
 $isChanged = serialize($this->model->$name) != serialize($value);
 $this->model->$name = $value;
 if ($isChanged){
 $this->save();
 //save serialized object to the DB
 }
 //set data store
 } else {
 echo 'Cannot set: Does not contain property '.$name;
 }
 }
 public function get_id() {
 return $this->id;
 }
 /**
  * Populate the model from the database
  * @param int $id
  */
 protected function populate() {
 
 $testClass = NULL;
 $this->connect();
 
 if ($this->id == 0){
 $this->save();
 return;
 }
 
 //get the serialized object from the database
 $query = sprintf("SELECT %s FROM %s WHERE id=%d LIMIT 1", $this->db_key, $this->db_table_name, (int)($this->id));
 $result = mysql_query($query);
 $this->check_result($result, $query);
 
 // Populate model with result
 $row = mysql_fetch_assoc($result);
 $testClass = unserialize($row[$this->db_key]);
 try {
 $this->model = $testClass;
 } catch (Exception $e) {
 print_r($e);
 $message  = " \nInvalid object retrieved from the database";
 die($message);
 } 
 }
 
 /**
  * Saves a serialized version of the object to the database
  */
 private function save(){
 $this->connect();
 if ($this->id == 0){
 //there is no previously existing model
 //create an entry
 $query = sprintf("INSERT INTO ".$this->db_table_name." (".$this->db_key.") VALUES ('%s')",mysql_real_escape_string($this->serialize()));
 $result = mysql_query($query);
 $this->check_result($result, $query);
 } else {
 $serializedObj = $this->serialize();
 //save the serialized object to the DB
 $query = sprintf("UPDATE %s SET %s = '%s' WHERE id=%d", $this->db_table_name, $this->db_key, mysql_real_escape_string($serializedObj), $this->id);
 $result = mysql_query($query);
 $this->check_result($result, $query);
 }
 }
 
 private function check_result($result, $query){
 // Check result
 // This shows the actual query sent to MySQL, and the error.
 if (!$result) {
 $message  = 'Invalid query: ' . mysql_error() . "\n";
 $message .= 'Whole query: ' . $query;
 die($message);
 }
 }
 /**
  * Ensures that the object is connected to the database
  */
 private function connect(){
 //check to make sure these are defined 
 if (!isset($this->db_table_name)){
 die ('$db_table_name not defined');
 }
 if (!isset($this->db_key)){
 die ('$db_key not defined');
 }
 if (!isset($this->model)){
 die ('$model not defined');
 }
 if (!self::$database){
 self::$database = mysql_connect('localhost', DB_USER, DB_PASS);
 if (!self::$database) {
 die('Could not connect: ' . mysql_error());
 }
 $db_selected = mysql_select_db(DB_NAME, self::$database);
 if (!$db_selected) {
 die ('Can\'t use ' . DB_NAME . ' : ' . mysql_error());
 }
 }
 }
 
 /**
 * Serializes the entire object as a string for storage in the database
 * @return string
 */
 protected function serialize(){
 return serialize($this->model);
 }
 
}
/**
 * Model storing all data related to the dinning room
 * @author nicholasdunbar
 *
 */
class Dining_Room_Model{
 //number of tables in the restaurant
 public $tables = array();
 //number of waiters on the floor
 public $server_num = 0;
 //max amount of people that the floor can hold
 public $max_capacity_num = 0;
 //current number of customers in the dining room
 public $current_capacity_num = 0;
}
/**
 * Each time a property is changed this class will make sure the model is backed up to the database
 * @author nicholasdunbar
 *
 */
class Dining_Room_DB_Mapper extends DB_Property_Object {
 
 function __construct($init_id = 0) {
 $this->model = new Dining_Room_Model();
 $this->id = $init_id;
 $this->db_table_name = 'dinning_room';
 $this->db_key = 'object';
 $this->populate();
 }
 
 
 
}
//Chose the dinning room id. If the id is 0 then it 
//will create an id and you can retreive it with $dining_room->get_id();
$db_id = 1;
$dining_room = new Dining_Room_DB_Mapper($db_id);
//$dining_room->server_num = 20;
//$dining_room->max_capacity_num = 300;
//$dining_room->current_capacity_num = 120;
//$tables = $dining_room->tables;
//$tables[] = array("George","Paul","Linda");
//$tables[] = array("Josh","Suzy","Bob","Erin");
//$dining_room->tables = $tables;
echo $dining_room->server_num."\n";
echo $dining_room->max_capacity_num."\n";
print_r($dining_room->tables);
?>