Question

我写了一个plsql块，它将删除表中的重复数据。由于我写的逻辑是错误的，因此某些原始数据也会被删除，并且所做的更改已提交。请向我建议如何还原已提交的数据更改，并向我建议如何删除重复项

Answer 1

Flasback查询将用于还原oracle中已提交的更改。请在Google上搜索如何在Oracle中使用Falsback查询

Answer 2

您可以使用闪回功能来做到这一点。

1。SCN闪回

SELECT column_list
FROM table_name
AS OF SCN scn_number;

2。TIMESTAMP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;

让我们看一个例子：

要将表闪回到旧的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>

我在表中有四行。

SQL> ALTER TABLE string_ex ENABLE ROW MOVEMENT;

Table altered.

SQL>

需要行进。

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.
Flashback is complete

SQL> SELECT * FROM string_ex;

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

SQL>

我现在将表恢复为旧状态，并且该行返回了

通过：How to rollback my DB changes after a commit?

如何还原Oracle中已提交的更改

2 个答案:

您可以使用闪回功能来做到这一点。