<?php
class db_connect extends PDO{
    private $db_host = "localhost";
    private $db_name = "test.db";
    private $db_user = "katalog";
    private $db_pass = "parika825";
    private $db_table = "katalog";

    public function __construct(){
        parent::__construct("mysql:host{$this->db_host};dbname={$this->db_name}",$this->db_user, $this->db_pass);
    }
}
$con = new db_connect();
$stmt = $con->query("SELECT*FROM `$this->db_table`");
$result = $stmt->fetchALL();
?>