SQL> startup?
ORACLE instance started.?

Total System Global Area? 914358272 bytes?
Fixed Size????????????????? 2088184 bytes?
Variable Size???????????? 528483080 bytes?
Database Buffers????????? 377487360 bytes?
Redo Buffers??????????????? 6299648 bytes?
Database mounted.?
ORA-01157: cannot identify/lock data file 8 - see DBWR trace file?
ORA-01110: data file 8: '/var/opt/gssyneeadb/gssy_neeadb.dbf'?


SQL> ALTER SYSTEM SET "_allow_resetlogs_corruption"=TRUE SCOPE=SPFILE;?

System altered.?

SQL> shutdown?
ORA-01109: database not open?

Database dismounted.?
ORACLE instance shut down.?
SQL> startup mount?
ORACLE instance started.?

Total System Global Area? 914358272 bytes?
Fixed Size????????????????? 2088184 bytes?
Variable Size???????????? 528483080 bytes?
Database Buffers????????? 377487360 bytes?
Redo Buffers??????????????? 6299648 bytes?
Database mounted.?
SQL> alter database datafile '/var/opt/gssyneeadb/gssy_neeadb.dbf' offline drop;?

Database altered.?

SQL> shutdown?
ORA-01109: database not open?

Database dismounted.?
ORACLE instance shut down.?
SQL> startup?
ORACLE instance started.?

Total System Global Area? 914358272 bytes?
Fixed Size????????????????? 2088184 byte