Connection to database MySQL failed

i try to connect to MySQL DB via a PHP5 class but i didn't get it although my code is pretty correct, i make a class that contain function to establish connection and in other page i make instance and i call method that build connection but the connection is failed. here my class :

class ConnectionManipulationBaseDeDonnees {
    private $bdd;
    public function connection() {
        try {
            $pdo_options[PDO::ATTR_ERRMODE]=PDO::ERRMODE_EXCEPTION;
            $bdd=new PDO('mysql:host=localhost;dbname=ssiphone','root','',$pdo_options);
        }
        catch(Exception $e) {
            die('Erreur: '.$e->getMessage());
        }
    }
    public function bdd() {
        $this->connection();
        return $this->bdd;
    }
}

and in the other file my code for instantiation and invocation is :

include("../classes/ConnectionManipulationBaseDeDonnees.php开发者_如何学JAVA");

//on déclare une instance de connection de la classe 
$cnx = new ConnectionManipulationBaseDeDonnees();

//une variable qui contient l`accées à la base
$bdd = $cnx->bdd();

if ($bdd) {
    echo "connection succeeded";
} else {
    echo "connection failed";
}

i got always the message "connection failed".

Inside the function connection() in your class, change $bdd = new PDO(...) to $this->bdd = new PDO(...)