for my database assignment we were looking into 'database corruption' and I was asked to delete the second redo log file which I have done with the command: rm log02a.rdo this was in the $HOME/ORADATA/u03 directory.

Now I started up my database using startup pfile=$PFILE nomount then I mounted it using the command alter database mount; now when I try to open it alter database open; it gives me the error:

ORA-03113: end-of-file on communication channel 
Process ID: 22125 
Session ID: 25 Serial number: 1

I am assuming this is because the second redo log file is missing. There is still log01a.rdo, but not the one I have deleted. How can I go about recovering this now so that I can open my database again?

I have looked into the database created scripts, and it specified the log02a.rdo file to be size 10M and part of group 2.

If I do select group#, member from v$logfile; I get:

  1
/oradata/student_db/user06/ORADATA/u03/log01a.rdo

  2
/oradata/student_db/user06/ORADATA/u03/log02a.rdo

  3
/oradata/student_db/user06/ORADATA/u03/log03a.rdo

  4
/oradata/student_db/user06/ORADATA/u03/log04a.rdo

So it is part of group 2. If I try to add the log02a.rdo file again "already part of the database". If I drop group 2 and then add it again with these commands:

ALTER DATABASE 
  ADD LOGFILE GROUP 2 ('$HOME/ORADATA/u03/log02a.rdo')
      SIZE 10M;

Nothing. Supposedly alters the database, but it still won't start up. Any ideas what I can do to re-create this and be able to open my database again?