What is the best method to make sure two people don't edit the same row on my web app?

Question

I have a PHP/jQuery/AJAX/MySQL app built for managing databases. I want to implement the ability to prevent multiple users from editing the same database row at the same ti

Answer 1

Don't try to prevent it. Let them decide what to do in the case of an edit conflict.

Add a timestamp to the table. Compare the timestamp of when the row was retrieved with the current timestamp. Make them aware of changes between their load and their save, and let them decide what action to take.

So yeah, number 3.