This is going to be a terribly basic question to some of you. Really, I'm just looking for a high level overview so that I can confirm that I'm on the right track.

I've been modifying an existing module for my own purposes. I've released a 'light' customization already to my web site. It's being used now and everything is great. I'm not ready, however, to begin the process of making some of the bigger functional additions to the module to really tailor it to our processes. These changes involve database changes (adding some columns to a couple of tables to store more information).

All the changes up till now have not required an update script. I simply load the new version of the module up to the web site, and perform an 'Update' from the Modules Administration screen. I've tried changing the database structure and generating a new .sql file documenting the new structure. Running a simple update, however, breaks the module.

Now I've noticed that some module require you to execute an "update script" once after doing the official XOOPS update from the administration screen. This update script is a php file and, presumably, makes some heavy duty (table change related?) alterations behind the scenes. I guess I need to write such a script myself and run it in order to propagate a table change effectively.

So what I am asking for is someone to give me a high level overview of why update scripts are written and the types of operations that they typically perform.

Thank you in advance for any help received!

I would like the answer to this question also. I have the same problem: preexisting module and I have sql and data changes to make in the next version.

What do you mean by an update script? What is it called, and where did you place it?