Share libraries w/MySQL, guide:
Play it super safe; it's best to upgrade by: export your library, delete the old MySQL databases, upgrade to pre-Eden, then reimport the library. You will still need to set up MySQL to let XBMC create databases, as noted below.
When upgrading from XBMC v10 (Dharma) to XBMC v11 (Eden) you may need to make changes to your MySQL server. The user made for the MySQL DB ("XBMC" in most guides) will need access to create new databases. If the user already has that access then you don't need to do anything. If not, you will have to use the following command on your MySQL server:
GRANT ALL ON *.* TO 'xbmc';
The latest pre-Eden builds will make a copy of the current DB and upgrade the copy. That way if anything goes wrong in the upgrading you still have an original untouched copy of your DB. BACKUP YOUR DATABASE JUST IN CASE. Also EXPORT your library from your current version before beginning the upgrade process or you may find yourself starting your library from scratch.
Updating your library may take a few minutes, so be sure to give XBMC time to do its thing. Stopping midway will mess up the updated DB.
If your upgrade fails with database errors, you should edit your advancedsettings.xml and remove the lines <name>myvideos</name> and <name>mymusic</name>. They are only needed if you want to use multiple Video or Audio MySQL databases.