FLASHBACK DATABASE 
=======================================



描述 
-----------

用于从回收站中恢复被删除的DATABASE。

前置条件 
-------------

回收站需要处于开启状态，可以通过

`show variables like 'recyclebin';`

来查看回收站是否开启。

```javascript
OceanBase(admin@test)> show variables like 'recyclebin';
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| recyclebin    | ON    |
+---------------+-------+
1 row in set (0.00 sec)
```



果回收站处于关闭状态，可以通过

`set recyclebin = on;`

来开启。回收站中的表没有被实际删除，仍然会占用资源，如果需要彻底删除，可以执行

`purge recyclebin;`

格式 
-----------

```javascript
 FLASHBACK DATABASE object_name TO BEFORE DROP [RENAME TO db_name];
```



参数解释 
-------------



|   **参数**    |                                **解释**                                |
|-------------|----------------------------------------------------------------------|
| object_name | 指定要恢复的object名称，不支持指定DATABASE名称。恢复DATABASE时，也会将DATABASE下面的表、索引等都恢复出来。 |
| RENAME to   | 恢复时将DATABASE重命名。                                                     |



示例 
-----------

* 从回收站中恢复删除的DATABASE。




```javascript
OceanBase(admin@test)> create database da;
Query OK, 1 row affected (0.03 sec)

OceanBase(admin@test)> drop database da;
Query OK, 0 rows affected (0.04 sec)

OceanBase(admin@test)> show recyclebin;
+--------------------------------------------------+---------------+----------+----------------------------+
| OBJECT_NAME                                      | ORIGINAL_NAME | TYPE     | CREATETIME                 |
+--------------------------------------------------+---------------+----------+----------------------------+
| __recycle_$_1_1099511628829_18446744073709551615 | da            | DATABASE | 2017-10-20 17:36:15.838771 |
+--------------------------------------------------+---------------+----------+----------------------------+
1 row in set (0.02 sec)

OceanBase(admin@test)> flashback database __recycle_$_1_1099511628829_18446744073709551615 to before drop;
Query OK, 0 rows affected (0.03 sec)
```