This thread might help with some info about updating your DB:
http://www.eqemulator.net/forums/showthread.php?t=28245
But, if you just want to update to the latest SVN, all you should have to do is run the extra SQL that comes with it and make sure to get all of the required SQL added before starting your server up on the new code.
Also, it is a very good idea to backup your whole database before making any changes to it. Not worth risking a mistake.