oracle flashback

flashback database要求数据库必须处于归档模式

1) how to check if flashback function and log mode is open

    select dbid, name, log_mode,flashback_on from v$database;  --FLASHBACK_ON为NO，则表示闪回特性尚未启用

   (Another way to check log mode:  sql> archive log list;)

2）check how long history database can flash back to

  select oldest_flashback_scn, oldest_flashback_time from v$flashback_database;

2) how to set archivelog mode

   sql>  shutdown immediate

   sql>startup mount

   sql>archive log list;

   sql>alter database archivelog;

   sql>alter database open;

      check the status again: 

   sql> archive log list;

  sql>alter database flashback on;

(If meet the error not logged on when typing startup, that means the database disconnected wrong, can try startup force to start the database.)

Access RMAN:

type RMAN in terminal

RMAN>