An error occurred while deleting Oracle datafile.

1. in Oracle open mode, the datafile file is directly deleted from the OS.

Rm/u02/rmants. dbf

2. After the database is closed, the database cannot be opened and can only be mounted.

SQL> alter database open;
Alter database open
*
ERROR at line 1:
ORA-01157: cannot identify/lock data file 7-see DBWR trace file
ORA-01110: data file 7: '/u02/rmants. dbf'
3. Delete the data file in the mount status.

Alter database datafile '/u02/rmants. dbf' offline drop;

4. Open the database

Alter database open;

5. Verification status

Select open_mode from v $ database

OPEN_MODE
--------------------
READ WRITE