Oracle10g的Flashback version Query

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.

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 >