Johann, the steps as i see it: - add new uuid field for your new primary key, don't drop old one yet - fill in the uuid field - add a new foreign key field that will store UUID - use the old foreign key to lookup the uuid of the reference - store that uuid - alter tables to make the uuid fields the primary and foreign keys from the database's perspective - drop the old id columns
you'll have to do that with some sql scripting, and then update your web2py model files accordingly. good luck! christian

