J'ai un problème au niveau dans mon script

<?php

class database
{
    protected $connection = null;

    #make a connection
    public function __construct($db_host,$db_name,$db_user,$db_pass)
    {
	$db_host = "localhost";
	$db_name = "gestioncarriere";
	$db_user = "root";
	$db_pass = "";
	
	try{
		
		$db_con = new PDO("mysql:host={$db_host};dbname={$db_name}",$db_user,$db_pass);
		$db_con->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
	}
	catch(PDOException $e){
		echo $e->getMessage();
	}
}
}
?>