數據庫服務啓動。此時用sqlplus命令進入數據庫，出現SQL>提示。
此時執行語句卻發現ORA-01109: database not open
用alter database open出現錯誤
ORA-01113: file 2 needs media recovery
ORA-01110: data file 2: 'C:/ORACLE/PRODUCT/10.2.0/ORADATA/ORCL/UNDOTBS01.DBF'
查看數據庫和實例狀態
select status from v$instance;
STATUS
------------
MOUNTED
SQL> select open_mode from v$database;
OPEN_MODE
----------
MOUNTED
都市mounted狀態而不是open
於是，用命令recover datafile 'C:/ORACLE/PRODUCT/10.2.0/ORADATA/ORCL/UNDOTBS01.DBF';
提示Media recovery complete.
SQL> alter database open;
alter database open
*
ERROR at line 1:
ORA-01113: file 3 needs media recovery
ORA-01110: data file 3: 'C:/ORACLE/PRODUCT/10.2.0/ORADATA/ORCL/SYSAUX01.DBF'
反覆使用recover datafile，最後用alter database open打開了數據庫
再查看
SQL> select open_mode from v$database;
OPEN_MODE
----------
READ WRITE
對了。
recover datafile----->可改爲recover database.
再檢查
SQL> select instance_name, status from v$instance;
INSTANCE_NAME STATUS
---------------- ------------
orcl OPEN