1<?php
2class Database {
3  private static $instance;
4  private $connection;
5  
6  public function __construct() {
7    $this->connection = new PDO('mysql:host=localhost', 'user', 'pass');
8  }
9  
10  public static function getInstance() {
11    if (self::$instance === null) {
12      self::$instance = new Database();
13    }
14    return self::$instance;
15  }
16}
17?>