For those who struggle with maintaining their database schema, or who have problems applying updates and often revert them, there is a solution. Laravel, the MVC framework which I wrote about previously, offers you migrations.
On the surface, the migrations are simple sets of "up" and "down" methods that allow you to apply and remove the changes required for the migration. It also allows you to perform a "rollback" on the updates just made and a "reset" to clear out all changes and start over from the base. There's also a shortcut to help generate migration code from a configuration string.