For anyone that is interested in examining and (very carefully at your own risk) making changes to you Kobo Database, the link will take you to a SQLite database viewer.
http://sourceforge.net/projects/sqlitebrowser/
It is interesting to look at the data, but use great care and backup before you decide to make any changes on your Kobo reader or PC.
You can copy the KoboReader.sqlite from your .kobo folder, or the Kobo.sqlite from your PC.
Cheers
John in Sunny Carnarvon - Western Australia