<?php

class DBController
{

    private $host = "localhost";

    private $user = "root";

    private $password = "";

    private $database = "star_rating";

    private static $conn;


    function __construct()
    {
        $this->conn = new PDO('mysql:host=$this->host; dbname=$this->database',$this->user,$this->password);
        var_dump($a->conn);
    }
}

$a = new DBController;

die;