Flashback - Time Machine

We have already database in flashback mode. Let's see what option in gives us:

1. See object in a past:

SQL> select count(*) from t1;

  COUNT(*)
----------
    132027

SQL> select count(*) from t1 as of timestamp to_timestamp('2008-11-26 07:00:00','YYYY-MM-DD HH24:MI:SS');

  COUNT(*)
----------
     40001

Alternatively you can use SCN:

SQL>  SELECT SCN,
2     to_char(TIME_DP, 'YYYY-MM-DD HH24:MI:SS') TIME_DP
3     from sys.SMON_SCN_TIME
4     where to_char(TIME_DP,'YYYY-MM-DD HH24') = to_char(sysdate-1,'YYYY-MM-DD HH24')
5    order by SCN_BAS;

           SCN TIME_DP
-------------- ------------------------------
 8704635105759 2008-11-26 07:00:29
 8704635105915 2008-11-26 07:05:34
 8704635106215 2008-11-26 07:10:31
 8704635106316 2008-11-26 07:15:34
 8704635106420 2008-11-26 07:20:32
 8704635106521 2008-11-26 07:25:35
 8704635106631 2008-11-26 07:30:32
 8704635106735 2008-11-26 07:35:35
 8704635106839 2008-11-26 07:40:32
 8704635106940 2008-11-26 07:45:35
 8704635107058 2008-11-26 07:50:32
 8704635107159 2008-11-26 07:55:35

SQL> select count(*) from t1 as of scn 8704635105759;

  COUNT(*)
----------
     40001




2. Turn database to some point in time:

SQL>  EXECUTE dbms_Flashback.Enable_At_Time(to_date('2008-11-26 07:00:00','YYYY-MM-DD HH24:MI:SS'));

PL/SQL procedure successfully completed.

SQL> select count(*) from t1;

  COUNT(*)
----------
     40001

SQL> EXECUTE dbms_Flashback.disable;

PL/SQL procedure successfully completed.

SQL> select count(*) from t1;

  COUNT(*)
----------
    132027