SQL和PHP的新领域

Question

So I wanted to create a small cms I mean it's not even a CMS it's like a catalog for my needs and I found something on internet and changed few things.

But I need 2 more fields, but I use the same pattern to add them and I won't.

Here is the code:

http://pastebin.com/kfkFtUDd

I kno guys that this is the worst code you ever saw but it's only for local use!!

Almost forgot here is the connection and "admin" check.

  <?php

      include_once('_class/cms.php');
      $obj = new simpleCMS();

      $obj->host = 'localhost';
      $obj->username = 'root';
      $obj->password = '';
      $obj->table = 'custom_cms';
      $obj->connect();

      if ( $_POST )
        $obj->write($_POST);

      echo ( isset($_GET['admin']) && $_GET['admin'] == 1 ) ? $obj->display_admin() : $obj->display_public();


    ?>

Thanks in advance!