Oracle的闪回操作

Oracle10g中引入了闪回技术，但这并不意味着所有的表都能闪回成功，当没有足够的磁盘空间，Oracle将使用回收站中的磁盘空间,而且位图连接索引和引用完整性约束也不受回收站的保护。

recyclebin参数的设置

show parameter bin       --展示是否使用了闪回技术，默认是使用闪回技术的
alter session set recyclebin=off; 　　　　--在session级别修改
alter system set recyclebin=off DEFERRED;     --不加DEFERRED参数是不允许修改的,但在session一级可以修改，与10g不同

显示回收站中被删除的表

show recyclebin

删除或清空回收站中的表

purge table table_name;    --删除回收中的一张表
purge recyclebin;　　　　　--清空回收

恢复被删除的表

flashback table table_name to before drop;   

彻底删除表，不放进回收站

drop table table_name purge;

闪回错误的DML操作

在Oracle10g和11g中可以利用还原段中的数据进行恢复

设置还原段的保留时间

show parameter undo_retention    --查看保留时间，默认是15分钟
alter system set undo_retention=7200；   --修改保留时

下面以一个例子来进行说明

update myemp set sal=9999;                 --将myemp中的员工都变为9999

--通过version子句查询以往的事物操作信息，version_xid为事物号，minvalue为最小值，maxvalue为最大值
select versions_xid,empno,ename,sal from myemp versions between scn minvalue and maxvalue where empno=7900;
结果显示如下图，versions_xid为空，表明我们并未提交所做的DML操作
aaarticlea/png;base64,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" alt="" />

commit;     --提交再查询，结果如图：
aaarticlea/png;base64,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" alt="" />
conn system/manager
 select operation,START_SCN from flashback_transaction_query where xid=hextoraw('0A00020004050000');   --查找出事物随对应的SCN号
aaarticlea/png;base64,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" alt="" />
－－－不知道为什么表中显示状态为unknown，按理应该是ＵＰＤＡＴＥ的。
alter table scott.myemp enable row movement;　　　　－－开启表的行移动功能
flashback table scott.myemp to SCN 1996229;        --恢复操作完成

也可以按照时间点恢复

flashback table scott.myemp to timestamp to_timestamp('15:36','hh24:mi');