Child theme functions.php

You should put your code in your child theme’s functions.php file.

I believe that the documentation you reference is referring to the fresh state of the functions.php file and the fact that you don’t need to copy a parent theme’s functions into a child theme to use them.

Hata!: SQLSTATE[HY000] [1045] Access denied for user 'divattrend_liink'@'localhost' (using password: YES)