Control file recovery

Status of Status of Datafiles Response
Online Logs

1. Available Current If the online logs contain redo necessary for recovery, then restore a backup control file apply the logs during recovery. Hence, you must specify the filename of the online logs containing the changes in order to open the database. After recovery, open RESETLOGS.
2. Unavailable Current If the online logs contain redo necessary for recovery, then you must re-create the control file. Because the logs are inaccessible, open RESETLOGS.
3. Available Backup Restore a backup control file, perform complete recovery, and then open RESETLOGS.
4. Unavailable Backup Restore a backup control file, perform incomplete recovery, and then open RESETLOGS.

Above is the extract from Oracle User Managed recovery Guide, but not quite understood the 1st and 2nd points. May be i am missing a samll thing

Q1. In point 1 and also in point 3 , why do we have to do use Reset logs, even though we have the datafile and Online redo logs ? Q2. In point 2 it says "since the logs are inaccessible re-create the control file". Why do we have to create a new file? Why can't we use a backup control file and do incomplete recovery as in point 4? Received on Mon Sep 05 2005 - 05:49:19 CDT