Start Oracle Database with missing datafile

1. Suppose a media failure brings down the database and you try to start up the system after the media failure is corrected. To open the database, type

   STARTUP OPEN PFILE='C:\ORANT\DATABASE\INITORCL.ORA'
   

   at the prompt and press Enter.
   
2. You receive the message that a datafile is missing. From the name of the datafile, you know it belongs to the USER_DATA tablespace. Since the system is in the mount mode, you have to take the damaged datafile offline. Type

   ALTER DATABASE DATAFILE
   'C:\ORANT\DATABASE\USR1ORCL.ORA' OFFLINE;
   

   at the prompt and press Enter.
   
3. The database is now ready for startup. Type ALTER DATABASE OPEN; at the prompt and press Enter.
4. To start to restore the damaged datafile, you have to access the operating system. Type HOST at the prompt and press Enter.
5. To restore the damaged datafile, type COPY C:\ORANT\DATABASEX\BACKUPORCL\USR1ORCLE.ORA C:\ORANT\DATABASE\USR1ORCLE.ORA at the prompt and press Enter.
6. To return to Server Manager, type EXIT at the prompt and press Enter.
7. To start the recovery process, type RECOVERY AUTOMATIC DATAFILE 'C\ORANT\DATABASE\USR1ORCL.ORA'; at the prompt and press Enter.
8. The recovered datafile is ready to be put back online. Type ALTER DATABASE DATAFILE 'C:\ORANT\DATABASE\USR1ORCL.ORA' ONLINE; at the prompt and press Enter.
9. You have successfully completed three steps. You started the database with a missing datafile, recovered the damaged datafile, and you brought it back online. This completes the Simulation.