-rw-r----- 1 oracle oinstall 5251072 Mar 2 17:25 tyger2_01.dbf.bak
-rw-r----- 1 oracle oinstall 26222592 Mar 2 17:24 undotbs01.dbf
-rw-r----- 1 oracle oinstall 5251072 Mar 2 17:19 users01.dbf
[oracle@tyger ORCL]$ exit
exit
TYGERU2@ORCL>conn / as sysdba
Connected.
SYS@ORCL>shutdown abort
ORACLE instance shut down.
SYS@ORCL>startup
ORACLE instance started.
Total System Global Area 285212672 bytes
Fixed Size 1218992 bytes
Variable Size 138413648 bytes
Database Buffers 142606336 bytes
Redo Buffers 2973696 bytes
Database mounted.
ORA-01157: cannot identify/lock data file 6 - see DBWR trace file
ORA-01110: data file 6: '/u01/app/oracle/oradata/ORCL/tyger2_01.dbf'
SYS@ORCL>alter database datafile 6 offline drop;
Database altered.
SYS@ORCL>alter database open;
Database altered.
SYS@ORCL>conn tygeru2/tygeru2
Connected.
TYGERU2@ORCL>select count(*) from u2_t1;
select count(*) from u2_t1
*
ERROR at line 1:
ORA-00376: file 6 cannot be read at this time
ORA-01110: data file 6: '/u01/app/oracle/oradata/ORCL/tyger2_01.dbf'
结论：