1、用途：
清除oracle 回收站(recyclebin)中的表和索引并释放与其相关的空间，还可清空回收站，或者清除表空间中记录的已删除的部分表空间。 注意：purge后不能回滚和恢复。
2、语法：
3、示例说明：
1）首先查一下回收站：
SELECT * FROM RECYCLEBIN;
2）创建并删除同一表三次：
--版本1
CREATE TABLE recycle_tmp(version NUMBER(10));
INSERT INTO recycle_tmp VALUES(1);
COMMIT;
DROP TABLE recycle_tmp;
SELECT object_name, original_name, operation, droptime FROM RECYCLEBIN;
回收站有1条记录：
OBJECT_NAME ORIGINAL_NAME OPERATION DROPTIME
------------------------------ -------------------------------- --------- -------------------
BIN$Ncu0aCGFSXGwbg3KwS5nHA==$0 RECYCLE_TMP DROP 2014-05-28:22:00:06
--版本2
CREATE TABLE recycle_tmp(version NUMBER(10));
INSERT INTO recycle_tmp VALUES(2);
COMMIT;
DROP TABLE recycle_tmp;
SELECT object_name, original_name, operation, droptime FROM RECYCLEBIN;
回收站有2条记录：
OBJECT_NAME ORIGINAL_NAME OPERATION DROPTIME
------------------------------ -------------------------------- --------- -------------------
BIN$34btciE8RySPmHqIlCGnVg==$0 RECYCLE_TMP DROP 2014-05-28:22:03:49
BIN$Ncu0aCGFSXGwbg3KwS5nHA==$0 RECYCLE_TMP DROP 2014-05-28:22:00:06
--版本3
CREATE TABLE recycle_tmp(version NUMBER(10));
INSERT INTO recycle_tmp VALUES(3);
COMMIT;
DROP TABLE recycle_tmp;
SELECT object_name, original_name, operation, droptime FROM RECYCLEBIN;
回收站有3条记录：
OBJECT_NAME ORIGINAL_NAME OPERATION DROPTIME
------------------------------ -------------------------------- --------- -------------------
BIN$34btciE8RySPmHqIlCGnVg==$0 RECYCLE_TMP DROP 2014-05-28:22:03:49
BIN$pNtKhKu4TY+qYYIQhTsdgg==$0 RECYCLE_TMP DROP 2014-05-28:22:04:02
BIN$Ncu0aCGFSXGwbg3KwS5nHA==$0 RECYCLE_TMP DROP 2014-05-28:22:00:06
3）清空版本1（默认删除最早版本）
PURGE TABLE recycle_tmp;
SELECT object_name, original_name, operation, droptime FROM RECYCLEBIN;
OBJECT_NAME ORIGINAL_NAME OPERATION DROPTIME
------------------------------ -------------------------------- --------- -------------------
BIN$34btciE8RySPmHqIlCGnVg==$0 RECYCLE_TMP DROP 2014-05-28:22:03:49
BIN$pNtKhKu4TY+qYYIQhTsdgg==$0 RECYCLE_TMP DROP 2014-05-28:22:04:02
4）清空版本2（根据回收站OBJECT_NAME清除表）
PURGE TABLE "BIN$34btciE8RySPmHqIlCGnVg==$0";
SELECT object_name, original_name, operation, droptime FROM RECYCLEBIN;
OBJECT_NAME ORIGINAL_NAME OPERATION DROPTIME
------------------------------ -------------------------------- --------- -------------------
BIN$pNtKhKu4TY+qYYIQhTsdgg==$0 RECYCLE_TMP DROP 2014-05-28:22:04:02
5）还原版本3（使用闪回flashback）
--还原版本3
FLASHBACK TABLE recycle_tmp TO BEFORE DROP;
SELECT object_name, original_name, operation, droptime FROM RECYCLEBIN;
未选定行（此时回收站已空）
SELECT * FROM recycle_tmp;
VERSION
--------------------------
3
6）删除版本3，后清空回收站
DROP TABLE recycle_tmp;
PURGE RECYCLEBIN;
SELECT object_name, original_name, operation, droptime FROM RECYCLEBIN;
回收站已清空。 未选定行（已清空）
----------------------------- By Dylan.