闪回之 回收站、Flashback Drop （table、index、trigger等）

一： Flashback Drop 操作流程

模式一：drop table 后未新建同名表

SQL> create table flashdrop as select * from user_objects;
Table created.

SQL> create bitmap index ind_flashdrop on flashdrop(object_type);
Index created.

SQL> drop table flashdrop;
Table dropped.
--查看 recyclebin 内的对象
SQL> select original_name,object_name,type,droptime from recyclebin;
ORIGINAL_NAME OBJECT_NAME TYPE DROPTIME
-------------------------------- ------------------------------ ------------------------- -------------------
IND_FLASHDROP BIN$ESs42vP2YC3gUw0ZZAqeww==$0 INDEX 2015-03-13:08:08:19
FLASHDROP BIN$ESs42vP3YC3gUw0ZZAqeww==$0 TABLE 2015-03-13:08:08:19

SQL> flashback table flashdrop to before drop;
Flashback complete.

SQL> select original_name,object_name,type,droptime from recyclebin;
no rows selected
--查看索引名字
SQL> col column_name for a40
SQL> SELECT index_name, column_name, descend FROM user_ind_columns WHERE table_name = 'FLASHDROP';
INDEX_NAME COLUMN_NAME DESC
------------------------------ ---------------------------------------- ----
BIN$ESs42vP2YC3gUw0ZZAqeww==$0 OBJECT_TYPE ASC
--索引改为原来的名字 （说明 闪回表 后，即使未给索引重命名，执行计划依然可以走索引）
SQL> alter index "BIN$ESs42vP2YC3gUw0ZZAqeww==$0" rename to IND_FLASHDROP;
Index altered.
--查看是否成功改名
SQL> SELECT index_name, column_name, descend FROM user_ind_columns WHERE table_name = 'FLASHDROP';
INDEX_NAME COLUMN_NAME DESC
------------------------------ ---------------------------------------- ----
IND_FLASHDROP OBJECT_TYPE ASC

SQL> select count(*) from flashdrop;
COUNT(*)
----------
11
补充：
--查看表约束名
select CONSTRAINT_NAME,TABLE_NAME, COLUMN_NAME from user_cons_columns where TABLE_NAME='FLASHDROP';

模式二：drop table 后新建同名表

SQL> drop table flashdrop;
Table dropped.

SQL> create table flashdrop as select * from user_objects;
Table created.

SQL> select original_name,object_name,type,droptime from recyclebin;
ORIGINAL_NAME OBJECT_NAME TYPE DROPTIME
-------------------------------- ------------------------------ ------------------------- -------------------
IND_FLASHDROP BIN$ESs42vP4YC3gUw0ZZAqeww==$0 INDEX 2015-03-13:08:25:37
FLASHDROP BIN$ESs42vP5YC3gUw0ZZAqeww==$0 TABLE 2015-03-13:08:25:37

SQL> flashback table flashdrop to before drop;
flashback table flashdrop to before drop
*
ERROR at line 1:
ORA-38312: original name is used by an existing object

SQL> flashback table flashdrop to before drop rename to flashtable;
Flashback complete.

SQL> select original_name,object_name,type,droptime from recyclebin;
no rows selected

SQL> select count(*) from flashtable;
COUNT(*)
----------
11

模式三：drop table 后新建同名表，再 drop 新同名表

SQL> select count(*) from flashdrop;
COUNT(*)
----------
13

SQL> drop table flashdrop;
Table dropped.

SQL> create table flashdrop as select * from user_objects;
Table created.

SQL> insert into flashdrop(object_name) values('andy');
1 row created.

SQL> select count(*) from flashdrop;
COUNT(*)
----------
14
SQL> drop table flashdrop;
Table dropped.

SQL> select original_name,object_name,type,droptime from recyclebin;
ORIGINAL_NAME OBJECT_NAME TYPE DROPTIME
-------------------------------- ------------------------------ ------------------------- -------------------
FLASHDROP BIN$ESs42vP9YC3gUw0ZZAqeww==$0 TABLE 2015-03-13:08:42:21
FLASHDROP BIN$ESs42vP+YC3gUw0ZZAqeww==$0 TABLE 2015-03-13:08:56:16

SQL> select count(*) from "BIN$ESs42vP9YC3gUw0ZZAqeww==$0";
COUNT(*)
----------
13

SQL> select count(*) from "BIN$ESs42vP+YC3gUw0ZZAqeww==$0";
COUNT(*)
----------
14

SQL> flashback table "BIN$ESs42vP+YC3gUw0ZZAqeww==$0" to before drop;
Flashback complete.

SQL> select count(*) from flashdrop;
COUNT(*)
----------
14