Undo Removed Featured Images from database wordpress

Question

I was editing my WordPress theme and editing function.php

I used a code for not loading featured image file. but it seems the code removed the ability of loading featured image from database

i found the topic here and used it: http://spicemailer.com/wordpress/how-to-remove-featured-image-from-all-posts-wordpress/

how can i Undo it? It seems it has removed the link of my database to featured image,

• now there is no featured image in edit pages/posts of wordpress
• all my websites images which were features images are not displaying my website is : http://www.aryagostarafzar.com

please help me how to undo and set the link againg my last backup is for a week ago and i will lose many things

Answer 1

I had a look at the article. Unfortunately there is no reverse code for this situation as the query has deleted the records in the database.

If you had taken a backup of your database before running this query, you can restore it.

Otherwise, as mentioned in the articles your images are still available in the media library. So, you have to edit each post again and set the featured image on individual posts.