ALTER DATABASE DATAFILE OFFLINE

NOTE: The ALTER DATABASE DATAFILE OFFLINE DROP command, is not meant to allow you to remove a datafile. What the command really means is that you are offlining the datafile with the intention of dropping the tablespace. If you are running in archivelog mode, you can also use: ALTER DATABASE DATAFILE OFFLINE; instead of OFFLINE DROP. Once the datafile is offline, Oracle no longer attempts to access it, but it is still considered part of that tablespace. This datafile is marked only as offline in the controlfile and there is no SCN comparison done between the controlfile and the datafile during startup (This also allows you to startup a database with a non-critical datafile missing). The entry for that datafile is not deleted from the controlfile to give us the opportunity to recover that datafile.[@more@]