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Oracle10g通过Flashback Version Query提供查看对数据库事务级改变的方法.

 

当闪回事务处理查询与闪回版本查询同时使用时，我们可以轻易地从用户或者应用程序错误恢复。

 

以下是闪回版本查询的示例:

 

1.执行DML操作

 

EYGLE  on 30-MAR-05 >create table t as select username,user_id from dba_users;

 

Table created.

 

EYGLE  on 30-MAR-05 >select * from t;

 

USERNAME                          USER_ID

------------------------------ ----------

SYSTEM                                  5

SYS                                     0

TEST                                   25

EYGLE                                  26

SCOTT                                  29

DIP                                    19

TRANS                                  27

TEST1                                  28

OPERATOR                               31

WMSYS                                  23

DBSNMP                                 22

 

USERNAME                          USER_ID

------------------------------ ----------

OUTLN                                  11

 

12 rows selected.

 

EYGLE  on 30-MAR-05 >delete from t where username='OUTLN';

 

1 row deleted.

 

EYGLE  on 30-MAR-05 >commit;

 

Commit complete.

 

EYGLE  on 30-MAR-05 >delete from t where username='TEST1';

 

1 row deleted.

 

EYGLE  on 30-MAR-05 >commit;

 

Commit complete.

 

EYGLE  on 30-MAR-05 >select * from t;

 

USERNAME                          USER_ID

------------------------------ ----------

SYSTEM                                  5

SYS                                     0

TEST                                   25

EYGLE                                  26

SCOTT                                  29

DIP                                    19

TRANS                                  27

OPERATOR                               31

WMSYS                                  23

DBSNMP                                 22

 

10 rows selected.

 

EYGLE  on 30-MAR-05 >update t set user_id=1 where username='EYGLE';

 

1 row updated.

 

EYGLE  on 30-MAR-05 >commit;

 

Commit complete.

 

EYGLE  on 30-MAR-05 >delete from t where user_id >10;

 

7 rows deleted.

 

EYGLE  on 30-MAR-05 >commit;

 

Commit complete.

 

EYGLE  on 30-MAR-05 >select * from t;

 

USERNAME                          USER_ID

------------------------------ ----------

SYSTEM                                  5

SYS                                     0

EYGLE                                   1

 

EYGLE  on 30-MAR-05 >insert into t values('PENNY',2);

 

1 row created.

 

EYGLE  on 30-MAR-05 >commit;

 

Commit complete.

 

2.执行闪回版本查询

 

EYGLE  on 30-MAR-05 >select versions_starttime, versions_endtime, versions_xid,

  2          versions_operation, username,user_id

  3          from t versions between timestamp minvalue and maxvalue

  4  /

 

VERSIONS_STARTTIME             VERSIONS_ENDTIME               VERSIONS_XID     V USERNAME      USER_ID

------------------------------ ------------------------------ ---------------- - ---------- ----------

30-MAR-05 09.34.49 AM                                         000A000B000000F1 D DBSNMP             22

30-MAR-05 09.34.49 AM                                         000A000B000000F1 D WMSYS              23

30-MAR-05 09.34.49 AM                                         000A000B000000F1 D OPERATOR           31

30-MAR-05 09.34.49 AM                                         000A000B000000F1 D TRANS              27

30-MAR-05 09.34.49 AM                                         000A000B000000F1 D DIP                19

30-MAR-05 09.34.49 AM                                         000A000B000000F1 D SCOTT              29

30-MAR-05 09.34.49 AM                                         000A000B000000F1 D TEST               25

30-MAR-05 09.34.15 AM                                         0001001900000F0F U EYGLE               1

30-MAR-05 09.33.51 AM                                         00080016000000EF D TEST1              28

30-MAR-05 09.33.23 AM                                         0004000A000005EF D OUTLN              11

                                                                                 SYSTEM              5

 

VERSIONS_STARTTIME             VERSIONS_ENDTIME               VERSIONS_XID     V USERNAME      USER_ID

------------------------------ ------------------------------ ---------------- - ---------- ----------

                                                                                 SYS                 0

                               30-MAR-05 09.34.49 AM                             TEST               25

                               30-MAR-05 09.34.15 AM                             EYGLE              26

                               30-MAR-05 09.34.49 AM                             SCOTT              29

                               30-MAR-05 09.34.49 AM                             DIP                19

                               30-MAR-05 09.34.49 AM                             TRANS              27

                               30-MAR-05 09.33.51 AM                             TEST1              28

                               30-MAR-05 09.34.49 AM                             OPERATOR           31

                               30-MAR-05 09.34.49 AM                             WMSYS              23

                               30-MAR-05 09.34.49 AM                             DBSNMP             22

                               30-MAR-05 09.33.23 AM                             OUTLN              11

 

VERSIONS_STARTTIME             VERSIONS_ENDTIME               VERSIONS_XID     V USERNAME      USER_ID

------------------------------ ------------------------------ ---------------- - ---------- ----------

30-MAR-05 09.49.24 AM                                         00080006000000EF I PENNY               2

 

23 rows selected.

 

EYGLE  on 30-MAR-05 >

 

我们可以看到，以上事务的时间以及数据更改。