如何在提交后回滚我的数据库更改？

Question

我没有使用where子句进行数据库更新,并且没有进行任何备份就提交了.表中的所有行都会更新.有没有办法回滚这些变化？

DB是Oracle SQL的一个.请帮忙.

Answer 1

你可以使用闪回功能来做到这一点.

1. SCN的闪回

SELECT column_list
FROM table_name
AS OF SCN scn_number;

2. TIMESTAMP的闪回

SELECT column_list
FROM table_name
AS OF TIMESTAMP TO_TIMESTAMP('the timestamp value');

要获取current_scn和systimestamp,请查询:

SELECT current_scn, SYSTIMESTAMP
FROM v$database;

我们来看一个例子:

要将表闪回到旧scn,请使用FLASHBACK TABLE..TO SCN子句.

SQL> DROP TABLE string_ex PURGE;

Table dropped.

SQL> CREATE TABLE string_ex (sl_ps_code VARCHAR2(20) );

Table created.

SQL> INSERT INTO string_ex (sl_ps_code) VALUES ('AR14ASM0002');

1 row created.

SQL> INSERT INTO string_ex (sl_ps_code) VALUES ('AR14SFT0018');

1 row created.

SQL> INSERT INTO string_ex (sl_ps_code) VALUES ('AR14SFT0019');

1 row created.

SQL> INSERT INTO string_ex (sl_ps_code) VALUES ('AR14SFT0062');

1 row created.

SQL> COMMIT;

Commit complete.

SQL> SELECT current_scn, SYSTIMESTAMP FROM v$database;

         CURRENT_SCN SYSTIMESTAMP
-------------------- --------------------------------------------
      13818123201277 29-OCT-14 03.02.17.419000 PM +05:30

SQL> SELECT current_scn, SYSTIMESTAMP FROM v$database;

         CURRENT_SCN SYSTIMESTAMP
-------------------- --------------------------------------------
      13818123201280 29-OCT-14 03.02.22.785000 PM +05:30

SQL> SELECT current_scn, SYSTIMESTAMP FROM v$database;

         CURRENT_SCN SYSTIMESTAMP
-------------------- --------------------------------------------
      13818123201282 29-OCT-14 03.02.26.781000 PM +05:30

SQL> SELECT * FROM string_ex;

SL_PS_CODE
---------------
AR14ASM0002
AR14SFT0018
AR14SFT0019
AR14SFT0062

SQL>

我在表格中有四行.

SQL> ALTER TABLE string_ex ENABLE ROW MOVEMENT;

Table altered.

SQL>

行移动是必需的.

SQL> DELETE FROM string_ex WHERE ROWNUM =1;

1 row deleted.

SQL>
SQL> COMMIT;

Commit complete.

SQL>
SQL> SELECT * FROM string_ex;

SL_PS_CODE
---------------
AR14SFT0018
AR14SFT0019
AR14SFT0062

我现在删除了一行并提交了更改.

SQL> FLASHBACK TABLE string_ex TO SCN 13818123201277;

Flashback complete.

闪回完成

SQL> SELECT * FROM string_ex;

SL_PS_CODE
---------------
AR14ASM0002
AR14SFT0018
AR14SFT0019
AR14SFT0062

SQL>

我现在把我的桌子放到旧状态,然后排回来了