<?php
 class database{
function __construct()
{
    $db_user="root";
    $db_pass="";
    try {
        $con = new PDO('mysql:host=localhost;dbname=hrm', $db_user, $db_pass);
        $con->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
       }
      catch(PDOException $e)
      {
            echo $e->getMessage();
        }
    }
}

<?php

session_start();

 class user
  {

 private $db;

 function __construct(){

    require_once "../dbconfig.php";
     $this->db= new database();
  }