oracle 快速恢复表删除的某行数据

请问下,我删除表的某些数据,如何把它闪回来呀? 20分钟内不过对该表由插入了些数据
根据scn号来查询
select a, b, c, versions_xid, versions_starttime, versions_endtime,
versions_startscn,versions_endscn,versions_operation
  from test versions between scn 339493 and 339635
根据时间也可以
from test versions between timestamp
      to_date('2008-09-23 16:09:00','yyyy-mm-dd hh24:mi:ss')
  and to_date('2008-09-23 16:45:00','yyyy-mm-dd hh24:mi:ss')
select a, b, c, versions_xid, versions_starttime, versions_endtime,
versions_startscn,versions_endscn,versions_operation
  from test versions between timestamp minvalue and maxvalue
这个记录闪回全部数据
Insert Into BA.T_WAP_FINANCE_ANALYZ
select *
 
 from BA.T_WAP_FINANCE_ANALYZ versions between timestamp
      to_date('2009-12-21 9:00:00','yyyy-mm-dd hh24:mi:ss')
  and to_date('2009-12-21 11:00:00','yyyy-mm-dd hh24:mi:ss') 
    Where f_yearweek ='200947'
它保留表的每行最后次更改前的记录确对吧?
db_recovery_file_dest
db_recovery_file_dest_size
上面的是 如果UNDO 无法闪回数据,而且你无法确定时间,那么恢复区看看可有你的数据在,有的话就根据时间标志插回原始表