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。
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