flashback得简单用法

1.闪回查询，查询某个时间点的数据：

SQL> select systimestamp from dual;

SYSTIMESTAMP
--------------------------------------------------------------------------------
24-12月-07 03.27.26.790000 下午 +08:00

SQL> Select * from SCOTT.Emp
  2  /

EMPNO ENAME      JOB         MGR HIREDATE          SAL      COMM DEPTNO
----- ---------- --------- ----- ----------- --------- --------- ------
 7524 WARD       SALESMAN   7698 22-Feb-81     1250.00    500.00     30
 7569 JONES      MANAGER    7839 02-Apr-81     2975.00               20
 7657 MARTIN     SALESMAN   7698 28-Sep-81     1250.00   1400.00     30
 7701 BLAKE      MANAGER    7839 01-May-81     2850.00               30
 7785 CLARK      MANAGER    7839 09-Jun-81     2450.00               10
 7791 SCOTT      ANALYST    7566 19-Apr-87     3000.00               20
 7842 KING       PRESIDENT       17-Nov-81     5000.00               10
 7847 TURNER     SALESMAN   7698 08-Sep-81     1500.00      0.00     30
 7879 ADAMS      CLERK      7788 23-May-87     1100.00               20
 7903 JAMES      CLERK      7698 03-Dec-81      950.00               30
 7905 FORD       ANALYST    7566 03-Dec-81     3000.00               20
 7937 MILLER     CLERK      7782 23-Jan-82     1300.00               10

SQL> delete from SCOTT.Emp where empno=7903;

1 row deleted

SQL> commit;

Commit complete

SQL> select systimestamp from dual;

SYSTIMESTAMP
--------------------------------------------------------------------------------
24-12月-07 03.28.27.232000 下午 +08:00

SQL> Select * from SCOTT.Emp AS OF timestamp TO_TIMESTAMP('2007-12-24 15:27:26','YYYY-MM-DD HH24:MI:SS');

EMPNO ENAME      JOB         MGR HIREDATE          SAL      COMM DEPTNO
----- ---------- --------- ----- ----------- --------- --------- ------
 7524 WARD       SALESMAN   7698 22-Feb-81     1250.00    500.00     30
 7569 JONES      MANAGER    7839 02-Apr-81     2975.00               20
 7657 MARTIN     SALESMAN   7698 28-Sep-81     1250.00   1400.00     30
 7701 BLAKE      MANAGER    7839 01-May-81     2850.00               30
 7785 CLARK      MANAGER    7839 09-Jun-81     2450.00               10
 7791 SCOTT      ANALYST    7566 19-Apr-87     3000.00               20
 7842 KING       PRESIDENT       17-Nov-81     5000.00               10
 7847 TURNER     SALESMAN   7698 08-Sep-81     1500.00      0.00     30
 7879 ADAMS      CLERK      7788 23-May-87     1100.00               20
 7903 JAMES      CLERK      7698 03-Dec-81      950.00               30
 7905 FORD       ANALYST    7566 03-Dec-81     3000.00               20
 7937 MILLER     CLERK      7782 23-Jan-82     1300.00               10

12 rows selected