Backup/Recover datafile doubts..11

Thanks Keith Boulton,

I have few more things to get cleared.
I was actually experimenting with dbf files for checking the functionality of
backup/restore command in unix for restoring database files. My fear is that has the database file has not been corrupted after restore from tape
using unix restore command.
The same problem occurs even if tar command on unix is used to extract dbf files.
There is no Media failure if dbf file is moved/copied to other filesystem and replaced
back without archiving into tape..how is this ...?. So,has the restore or tar command corrupted the file .

Thanks
Vidya.

[Original message]
Hi ,

I had backed a Oracle dbf file using backup / restore commands of Unix and restored from tape with unix command. Then from the Oracle Server Manager I put the file into the database but
it resulted in Media failure.
Perhaps due to data corruption.
I did "alter database <database name>

             recover datafile <path where the datafile has been copied" On doing this the database got connected. Since I am not a DBA I have these set of doubts : Now , my doubts are how has this "alter database ..." command helped in correcting the restored dbf file.
But, my DBA friend told me that "alter database ..." command has helped

the newer
restored file in getting seq with Ctrl and database file , is it right ?

If yes ,, please tell me how.

I also got information like it is mandatory process to do "alter database ..." command
after recovering dbf files from tapes or any archive device. Is this also true ?

Thanks ,
Vidya Received on Tue Nov 23 1999 - 00:06:19 CST