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HomeDatabaseMysql TutorialOracle的recyclebin

Oracle10G以前执行drop table后表就即被删除了。10G后引入了垃圾回收站的概念recyclebin。如果仍只是drop table xxx,表不会立即

Oracle10G以前执行drop table后表就即被删除了。10G后引入了垃圾回收站的概念recyclebin。如果仍只是drop table xxx,表不会立即被删除,而是被暂时放入回收站。
可以保障某些误操作后还可以将表还原。

1.查看数据库是否开户recyclebin功能
SQL> show parameter recyclebin;

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
recyclebin                           string      on

或者只将当前会话开启功能
alter session set recyclebin = on;
2.查看当前用户中的垃圾回收站的对象:
select * from recyclebin;

3.drop table xxx时,不希望将表放入垃圾回收站,,而是直接drop
drop table xxx purge;

4.将recyclebin中对象还原或清除
--还原
flashback table "xxxxx" to before drop
"xxxx"乃是recyclebin视图中OBJECT_NAME字段名称
flashback table "xxxxx" to before drop
亦可换成
flashback table "xxxxx" to before drop  rename to xxxx重命名

--清除
purge table xxxx

purge recyclebin
还可以指定某个表空间和某个用户下表。

ps:
recycelbin中还保留了index。
如个表空间不够创建新对象时,oracle将自动请除recyclebin中的对象。
以下几种drop不会将相关对象放进RecycleBin:

    * drop tablespace:会将RecycleBin中所有属于该tablespace的对象清除
    * drop user:会将RecycleBin中所有属于该用户的对象清除
    * drop cluster:会将RecycleBin中所有属于该cluster的成员对象清除
    * drop type:会将RecycleBin中所有依赖该type的对象清除

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