This module is for fairly advanced Drupal users. It helps manage database settings as they are shared between multiple developers, and also between dev, staging and live versions of a website.
Read the (verbose) introduction.
Be sure to read the README.txt before you enable and use the module! Once enabled:
a) There's a special copy of Drupal where the settings can be changed. It's called the "base".
b) Each table might contain settings and data. It uses database settings to reserve a range of IDs.
The site_update.module does some of the work for you. You have to remember to make settings changes on the special "base" copy of you site. And use a special script to "dump" those settings to a file. The file can then be treated like source code. So it can be checked into a version control system and shared among developers that way.
It is a little tricky to start using site_update on a site that already has a large database. It works best when you use it from the very beginning of every project. I highly recommend you give it a try on your next Drupal site.
Known problems and limitations include:
* The 2.x branch is close to being database agnostic. Primarily tested on mysql, but the goal is to work with any database.