First, many thanks for all the developers of moodle...
To upgrade from 1.2beta to 1.2 final release, do we need to backup the data (mysql base) ?
Does the upgrade modify the mysql base or is it simply the php files and other who are changing ?
As Dale, I didn't backup my DB before and everything worked perfectly; but as a wise guy, you should backup it before any upgrade
IMHO - Always, always and I mean ALWAYS backup up your database, config, courses and if possible entire site before any major upgrade, especially if you are live and not in development.
This includes creating a backup NOT on the same server for those who have their own servers up and running.
my .02 - same advice goes out to all my clients some of which they actually follow