Disconnecting Users

Up until recently, it was not possible to get users cleanly off the database. The options you had were

From 7.3, Oracle sneaked a "shutdown transactional" mode into the database, which waited for everyone to complete active transactions before shutdown, which they then documented in the 8.0 and (I think) 7.3.4 release.

From 8i onwards, there is now a facility to have this transactional control at a session level. The new syntax is

alter system disconnect session 'sid,serial#' post_transaction;