Actually there isn't any official database scheme available.
There where some rumors a while back that Avaya (after the purchase of Agile CCE) would make this available, but it was later demoted because of customization and/or direct access of database items is not supported and no document would be released.
However, a bit old, but still very helpful is this document that was posted by someone on the old Avaya CCE forum (now closed down)
Comment