閃回數據庫方法可以用sqlplus，也可以用RMAN執行：
SQL> FLASHBACK DATABASE TO TIMESTAMP(''); --(基於時間點)
SQL> FLASHBACK DATABASE TO SCN ; --(基於SCN)
SQL> FLASHBACK DATABASE TO RESTORE POINT ; --(基於sestore point ，創建命令create restore point 名稱)
RMAN> FLASHBACK DATABASE TO TIME = "TO_DATE('2009-05-27 16:00:00', 'YYYY-MM-DD HH24:MI:SS')";--(基於時間點)
RMAN> FLASHBACK DATABASE TO SCN=23565; --(基於SCN)
RMAN> FLASHBACK DATABASE TO SEQUENCE=223 THREAD=1; --（序列號，可用list incarnation of database 查看當前sequence)
上述兩種方法都可以實現flashback database需要注意的是操作完成後使用命令打開數據庫alter database open resetlogs
下面來演示下基於時間點的閃回數據庫實驗：
1.查看當前歸檔
SQL> archive log list
Database log mode Archive Mode
Automatic archival Enabled
Archive destination USE_DB_RECOVERY_FILE_DEST
Oldest online log sequence 25
Next log sequence to archive 27
Current log sequence 27
2.查看下閃回數據庫打開沒，如果沒打開使用alter database flashback on命令打開
SQL> select flashback_on from v_$database;
FLASHBACK_ON
------------------
YES
3.先查詢當前時間
SQL> select to_char(sysdate,'yyyy-mm-dd:hh24:mi:ss') from dual;
TO_CHAR(SYSDATE,'YY
-------------------
2017-07-17:16:16:45
4.切換HR用 ，用HR建個表TMP717並 插入一行數據，接着把表刪除（加上PURGE），用DBA用戶切換日誌
SQL> conn hr/123456
Connected.
SQL> create table tmp717 (cons_no varchar2(10));
Table created.
SQL> insert into tmp717 values('1');
1 row created.
SQL> commit;
Commit complete.
SQL> select to_char(sysdate,'yyyy-mm-dd:hh24:mi:ss') from dual;
TO_CHAR(SYSDATE,'YY
-------------------
2017-07-17:16:20:47
SQL> drop table tmp717 purge
2 ;
Table dropped.
SQL> conn / as sysdba
Connected.
SQL> alter system switch logfile;
System altered.
SQL> archive log list
Database log mode Archive Mode
Automatic archival Enabled
Archive destination USE_DB_RECOVERY_FILE_DEST
Oldest online log sequence 26
Next log sequence to archive 28
Current log sequence 28
（當前日誌變成28）
5.關閉數據庫，啓動到MOUNT狀態（閃回數據庫必須的操作）
SQL> shutdown immediate
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> startup mount
ORACLE instance started.
Total System Global Area 820236288 bytes
Fixed Size 1339628 bytes
Variable Size 549457684 bytes
Database Buffers 264241152 bytes
Redo Buffers 5197824 bytes
Database mounted.
SQL> exit
6.打開RMAN進行閃回操作
[oracle@station4 ~]$ rman target /
Recovery Manager: Release 11.2.0.1.0 - Production on Mon Jul 17 16:31:13 2017
Copyright (c) 1982, 2009, Oracle and/or its affiliates. All rights reserved.
connected to target database: ORCL (DBID=1359978017, not open)
RMAN> list incarnation of database ;--（先查看下當前化身）
List of Database Incarnations
DB Key Inc Key DB Name DB ID STATUS Reset SCN Reset Time
------- ------- -------- ---------------- --- ---------- ----------
1 1 ORCL 1359978017 PARENT 1 13-AUG-09
2 2 ORCL 1359978017 CURRENT 754488 22-NOV-13
RMAN> run {
2> sql "alter session set nls_date_format=''YYYY-MM-DD:HH24:MI:SS''";
3> set until time '2017-07-17:16:20:47';
4> restore database;
5> recover database;}
7.用RESETLOGS打開數據庫，並查詢表還原成功
SQL> alter database open resetlogs;
Database altered.
SQL> select * from hr.tmp717;
CONS_NO
----------
1
8.重新查看化身
RMAN> list incarnation of database;
List of Database Incarnations
DB Key Inc Key DB Name DB ID STATUS Reset SCN Reset Time
------- ------- -------- ---------------- --- ---------- ----------
1 1 ORCL 1359978017 PARENT 1 13-AUG-09
2 2 ORCL 1359978017 PARENT 754488 22-NOV-13
3 3 ORCL 1359978017 CURRENT 1083685 17-JUL-17
上述實驗也可以用SQL> FLASHBACK DATABASE TO TIMESTAMP('2017-07-17:16:20:47'); 操作結果是一樣的
實驗中看出化身了一個，當前化身號是1083685，並且刪除的表還原回來了，表示成功執行。