在ORACLE 10g中引入了RECYCLE BIN这个东东，好处就是当你删除了一张表或索引什么的后并不是完全删除，就像WINDOWS中的回收站一样，好处就是防止误删除，可以对误删除的表进行恢复，当然也可以清空RECYCLE BIN。
介绍下RECYCLEBIN里一些简单的东西
先建立一张表，名FOO
SQL>CREATE TALBE FOO(ID NUMBER(5),NAME VARCHAR2(5));
查看当前SCHEME下的所有表的名字
SQL>SELECT TALBE_NAMES FROM USER_TALBES;
TABLE_NAME
------------------------------
FOO
删除表FOO
SQL>DROP TALBE FOO;
SQL>SELECT TALBE_NAMES FROM USER_TALBES;
TABLE_NAME
------------------------------
BIN$Z2ptJ6PcRk6mJbM/0BmmAg==$0
--如果只想看RECYCLEBIN内的表名，可以用 SELECT OBJECT_NAME FROM USER_RECYCLEBIN;效果同上显示
发现有一个名为'BIN$Z2ptJ6PcRk6mJbM/0BmmAg==$0'的表，这个表就是FOO表DROP掉以后在RECYCLE BIN内产生的表，RECYCLE BIN会以特殊的方法来保证每张被删除的表在RECYCLE BIN内的表名都不一样，即使在未被删除时表名是相同的。
如果想看被删除表的详细点的内容，可用
SQL>SHOW RECYCLEBIN; --这句在SQL*PLUS内可用，但PL/SQL DEV中显示不出内容，不知道怎么会事
或着
SQL>SELECT ORIGINAL_NAME,OBJECT_NAME,TYPE,DROPTIME FROM USER_RECYCLEBIN;
ORIGINAL_NAME OBJECT_NAME TYPE DROPTIME
-------------------------------- ------------------------------ ------------------------- -------------------
FOO BIN$Z2ptJ6PcRk6mJbM/0BmmAg==$0 TABLE 2007-11-18:21:53:02
也可以用
SQL>DESC "BIN$Z2ptJ6PcRk6mJbM/0BmmAg==$0"; --来看被删除表的结构，注意要双引号!!这一句
PL/SQL DEV中也不能用，会显示没有这个表，在SQL*PLUS中可用。
现在对删除后表名的命名简单说一下：
当一个表被删除并移动到"回收站"中，它的名字要进行一些转换。这样的目的显而易见是为了避免同类对象名称的重复。(这一点和Windows操作系统的回收站不同，Windows中的回收站经过了特殊的处理，操作系统文件可以重名。)
转换后的名字格式如下:
BIN$unique_id$version 其中BIN代表RecycleBin
unique_id是数据库中该对象的唯一标志，26个字符长度
version表示该对象的版本号
删除recyclebin中的对象
我们用PURGE，语句PURGE TABLE "TABLE_NAME";
注：双引不要忘记，对RECYCLEBIN中对象操作都要有" "。
如上例,则：
SQL>purge table "BIN$6qAKR9ljQo+l+1gDCV8xCQ==$0";
SQL>PURGE RECYCLEBIN; --可以清空RECYCLEBIN；
恢复recyclebin中的对象
我们用FLASHBACK，中文名"闪回"
语句FLASHBACK TABLE [已删除TABLE名|"RECYCLEBIN中的名字"] TO BEFORE DROP;
如上例，则：
SQL>FLASHBACK TABLE FOO TO BEFORE DROP;
闪回完成。
但当你在RECYCLEBIN内有2张相同名字的表时候，只有通过"RECYCLEBIN中的名字"来闪回指定的表,用上面方法只闪回第一个被删除的同名表。
http://blog.chinaunix.net/space.php?uid=8824503&do=blog&cuid=425448
Oracle10中增加的回收站的功能：
1.查看所有与回收站有关的数据对象：
SQL> SELECT T.OWNER,T.OBJECT_NAME,T.OBJECT_TYPE FROM ALL_OBJECTS T WHERE T.OBJECT_NAME LIKE '%RECYCLE%';
OWNER OBJECT_NAME OBJECT_TYPE
------------------------------ ------------------------------ -------------------
SYS RECYCLEBIN$ TABLE
SYS RECYCLEBIN$_OBJ INDEX
SYS RECYCLEBIN$_TS INDEX
SYS RECYCLEBIN$_OWNER INDEX
SYS USER_RECYCLEBIN VIEW
PUBLIC USER_RECYCLEBIN SYNONYM
PUBLIC RECYCLEBIN SYNONYM
SYS DBA_RECYCLEBIN VIEW
PUBLIC DBA_RECYCLEBIN SYNONYM
2.查看回收站的东西:
SQL> SHOW RECYCLEBIN
仅仅列出OBJECT_NAME,ORIGINAL_NAME,TYPE,DROPTIME四列。
ORIGINAL NAME RECYCLEBIN NAME OBJECT TYPE DROP TIME
---------------- ------------------------------ ------------ -------------------
A BIN$R+MY75CQQr+U9AGzM0MJ1Q==$0 TABLE 2009-01-10:16:02:35
B BIN$tnTJEnUFSiOVfgMGQJD4NA==$0 TABLE 2009-01-10:16:02:44
C1 BIN$V+zsHnmGSLe0aaG+UOkWIw==$0 TABLE 2009-01-10:16:02:54
STUDENT BIN$zV1QAvZLRF6QUJk1kd9MBg==$0 TABLE 2008-12-28:17:31:20
T BIN$0Xc7bFJlQlOhoAan/bp4Fw==$0 TABLE 2008-12-14:19:42:19
T2 BIN$WuDMiaqgRraE4AwfZyKR1w==$0 TABLE 2009-01-10:16:03:22
3.查看recycle视图的定义
SQL> DESC RECYCLEBIN
Name Type Nullable Default Comments
-------------- ------------ -------- ------- --------------------------------------------------------
OBJECT_NAME VARCHAR2(30) New name of the object
ORIGINAL_NAME VARCHAR2(32) Y Original name of the object
OPERATION VARCHAR2(9) Y Operation carried out on the object
TYPE VARCHAR2(25) Y Type of the object
TS_NAME VARCHAR2(30) Y Tablespace Name to which object belongs
CREATETIME VARCHAR2(19) Y Timestamp for the creating of the object
DROPTIME VARCHAR2(19) Y Timestamp for the dropping of the object
DROPSCN NUMBER Y SCN of the transaction which moved object to Recycle Bin
PARTITION_NAME VARCHAR2(32) Y Partition Name which was dropped
CAN_UNDROP VARCHAR2(3) Y User can undrop this object
CAN_PURGE VARCHAR2(3) Y User can undrop this object
RELATED NUMBER Parent objects Obj#
BASE_OBJECT NUMBER Base objects Obj#
PURGE_OBJECT NUMBER Obj# for object which gets purged
SPACE NUMBER Y Number of blocks used by this object
4.详细查看具体的
SQL> SELECT T.OBJECT_NAME,T.ORIGINAL_NAME,T.TYPE,T.DROPTIME,T.CREATETIME FROM RECYCLEBIN T;
OBJECT_NAME ORIGINAL_NAME TYPE DROPTIME CREATETIME
------------------------------ -------------------------------- ------------------------- ------------------- -------------------
BIN$0Xc7bFJlQlOhoAan/bp4Fw==$0 T TABLE 2008-12-14:19:42:19 2008-10-11:23:01:11
BIN$ccbejyZCQ4udSL2iQk83Ww==$0 PK_STUDENT_ID INDEX 2008-12-28:17:31:19 2008-12-28:17:27:21
BIN$UyiSWkrGRRSYCbZ4w97ptg==$0 T_TRIGGER TRIGGER 2008-12-14:19:42:19 2008-10-26:15:37:14
BIN$zV1QAvZLRF6QUJk1kd9MBg==$0 STUDENT TABLE 2008-12-28:17:31:20 2008-12-28:17:27:20
BIN$R+MY75CQQr+U9AGzM0MJ1Q==$0 A TABLE 2009-01-10:16:02:35 2008-10-30:22:01:26
BIN$tnTJEnUFSiOVfgMGQJD4NA==$0 B TABLE 2009-01-10:16:02:44 2008-10-30:22:03:44
BIN$V+zsHnmGSLe0aaG+UOkWIw==$0 C1 TABLE 2009-01-10:16:02:54 2008-10-26:16:05:42
BIN$WuDMiaqgRraE4AwfZyKR1w==$0 T2 TABLE 2009-01-10:16:03:22 2008-10-26:15:36:19
BIN$aFjB3kaNQmacc1irUBJfsg==$0 TT_TRIGGER TRIGGER 2009-01-10:16:03:22 2008-10-26:15:39:22
BIN$4I6nffFIQjeGv3jKsc4Xow==$0 T3 TABLE 2009-01-10:16:03:22 2008-10-26:15:38:45
BIN$9gb8zixHSGqKGH96Te1/gQ==$0 TEST TABLE 2009-01-10:16:03:22 2008-10-12:21:21:46
BIN$DxduMzI4RdqPL/UFxOJe+w==$0 TEST1 TABLE 2009-01-10:16:03:22 2008-10-12:21:23:37
BIN$egeKA5GkThWaiHe/0GixPQ==$0 TEST2 TABLE 2009-01-10:16:03:22 2008-10-12:21:28:39
BIN$GXH7XLqTQTGbjwzzlrNt6g==$0 TEST3 TABLE 2009-01-10:16:03:22 2008-10-12:21:49:29
BIN$Gouz6KxTS+2ac55DqAYJiQ==$0 TEST4 TABLE 2009-01-10:16:03:22 2008-10-12:22:11:55
BIN$Sg1vjzx0TIW3m9lmCWMqQg==$0 TEST5 TABLE 2009-01-10:16:03:22 2008-10-12:22:13:34
BIN$7IuwzwIER2ew1nm0j7jSTw==$0 TEST6 TABLE 2009-01-10:16:03:22 2008-10-15:22:03:39
BIN$UuoORCOETPCYuEY7indiSg==$0 TT TABLE 2009-01-10:16:03:22 2008-10-26:16:10:49
BIN$n9q6RusoSlmfbRngZftmPA==$0 TT3 TABLE 2009-01-10:16:03:23 2008-10-29:21:07:25
5.清除一个表：
SQL> PURGE TABLE "BIN$UuoORCOETPCYuEY7indiSg==$0";
Done
6.清除回收站：
SQL> PURGE RECYCLEBIN;
Done
SQL> SELECT T.OBJECT_NAME,T.ORIGINAL_NAME,T.TYPE,T.DROPTIME,T.CREATETIME FROM RECYCLEBIN T;
OBJECT_NAME ORIGINAL_NAME TYPE DROPTIME CREATETIME
------------------------------ -------------------------------- ------------------------- ------------------- -------------------
6.恢复一个表：
SQL> DROP TABLE P1;
Table dropped
SQL> SELECT T.OBJECT_NAME,T.ORIGINAL_NAME,T.TYPE,T.DROPTIME,T.CREATETIME FROM RECYCLEBIN T;
OBJECT_NAME ORIGINAL_NAME TYPE DROPTIME CREATETIME
------------------------------ -------------------------------- ------------------------- ------------------- -------------------
BIN$wtP8UH7PSFqRKd5NzdUsgQ==$0 SYS_C005204 INDEX 2009-01-11:15:54:22 2008-10-26:16:04:26
BIN$vaxMSW3YT/mOkJTp9VmtDw==$0 P1 TABLE 2009-01-11:15:54:22 2008-10-26:16:04:26
SQL> FLASHBACK TABLE P1 TO BEFORE DROP;
Done
SQL> SELECT * FROM TAB WHERE TNAME ='P1';
TNAME TABTYPE CLUSTERID
------------------------------ ------- ----------
P1 TABLE
7.不启用回收站：
SQL> ALTER SESSION SET RECYCLEBIN=OFF;
Session altered
SQL> PURGE RECYCLEBIN;
Done
SQL> DROP TABLE P1;
Table dropped
SQL> SELECT T.OBJECT_NAME,T.ORIGINAL_NAME,T.TYPE,T.DROPTIME,T.CREATETIME FROM RECYCLEBIN T;
OBJECT_NAME ORIGINAL_NAME TYPE DROPTIME CREATETIME
------------------------------ -------------------------------- ------------------------- ------------------- -------------------
8.设置启用或关闭回收站
SQL> ALTER SYSTEM SET RECYCLEBIN=OFF;
System altered
SQL> ALTER SYSTEM SET RECYCLEBIN=ON;
System altered
SQL> ALTER SESSION SET RECYCLEBIN=ON;
Session altered