Poo php

class Maclass{
	private $bdd;

	public function __construct($dbHost,$dbName,$dbUser,$dbPassWord){
		if(!self::$bdd){
			try{
				self::$bdd=new PDO('mysql:host='.$dbHost.';dbname='.$dbName,$dbUser,$dbPassWord);
				self::$bdd->setAttribute(PDO::ATTR_ERRMODE,PDO::ERRMODE_EXCEPTION);
			}catch(PDOException $e){
				echo'<pre>';print_r($e);echo'</pre>';
				exit();
			}
		}
	}
	
	public function req($sql,$fetch=0){
		try{
			if($fetch==0){
				return self::fetch(self::$bdd->query($sql));
			}else{
				return self::$bdd->query($sql);
			}
		}
		catch(PDOException $e){
			return false;
		}
	}

	public function fetch($a,$b='assoc'){
		if($b=='both'){return $a->fetch(PDO::FETCH_BOTH);}
		elseif($b=='assoc'){return $a->fetch(PDO::FETCH_ASSOC);}
		elseif($b=='bound'){return $a->fetch(PDO::FETCH_BOUND);}
		elseif($b=='class'){return $a->fetch(PDO::FETCH_CLASS);}
		elseif($b=='into'){return $a->fetch(PDO::FETCH_INTO);}
		elseif($b=='lazy'){return $a->fetch(PDO::FETCH_Lazy);}
		elseif($b=='num'){return $a->fetch(PDO::FETCH_NUM);}
		elseif($b=='obj'){return $a->fetch(PDO::FETCH_OBJ);}
		else{return false;}
	}
	
	public function __destruct(){}
}

$maclass=new Maclass('localhost','namebase','nameuser','passworduser');