<?php

define('DB_HOST', 'localhost');
define('DB_NAME', 'your student tag');
define('DB_USER', 'your student tag');
define('DB_PASS', 'your password');
define('DB_CHAR', 'utf8');

class DB
{
    protected static $instance = null;

    final private function __construct() {}
    final private function __clone() {}

    public static function instance()
    {
        if (self::$instance === null)
        {
			$opt  = array(
				PDO::ATTR_ERRMODE            => PDO::ERRMODE_EXCEPTION,
				PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC,
				PDO::ATTR_EMULATE_PREPARES   => TRUE,
				PDO::ATTR_STATEMENT_CLASS    => array('myPDOStatement'),
			);
            $dsn = 'mysql:host='.DB_HOST.';dbname='.DB_NAME.';charset='.DB_CHAR;
            self::$instance = new PDO($dsn, DB_USER, DB_PASS, $opt);
        }
        return self::$instance;
    }
    public static function __callStatic($method, $args) {
        return call_user_func_array(array(self::instance(), $method), $args);
    }
}

class myPDOStatement extends PDOStatement
{
	function texecute($data = array())
	{
		parent::execute($data);
		return $this;
	}
}