Normally when we restore the hot backup of a database, we will recover and open it with resetlogs option because during the restore procedure we have to restore the control file first.
Last week I got a request to migrate a database and was told if the migration were failed, then I had to insert the new change happened on the new database to the original database. There were huge number of tables and the target Oracle version was the same so I tried to find way to open the restored database without resetlogs option, so both databases should be considered as one database and the new archive logs could be applied to the original database if the migration failed.
I did a test before the final migration and found I could restore the database with hot backup as normal and also applied the archive logs to the latest one. Just before opened it with resetlogs option, I did below steps:
1. Shutdowned the original database cleanly
2. Replaced the restored backup controlfile with the original current controlfile
3. Copied all the original redo logs to the new restored database
4. Renamed all the data files, temp files and redo logs
5. Recovered the database continually and this time RMAN would not ask you to provide any archive log
6. Run command 'alter database open'.