flashback query实验（基于undo数据）
发布时间：2020-12-15 17:55:09 所属栏目：百科 来源：网络整理
导读：开启闪回：http://www.voidcn.com/article/p-okbbpchw-bbu.html ? 误操作DML语句，刚刚发生，undo没有被覆盖 1、查询原数据 11:52:06 scott@TEST0910 select count(*) from test10; ? ? COUNT(*) ---------- ??????? 14 ? 11:52:06 这个时间点还有数据，稍后
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开启闪回：http://www.voidcn.com/article/p-okbbpchw-bbu.html ?
误操作DML语句，刚刚发生，undo没有被覆盖
1、查询原数据
11:52:06 scott@TEST0910> select count(*) from test10;
?
? COUNT(*)
----------
??????? 14
?
11:52:06 这个时间点还有数据，稍后作为参考
2、误操作
11:52:19 scott@TEST0910> delete from test10;
?
14 rows deleted.
?
11:52:31 scott@TEST0910> commit;
?
Commit complete.
?
11:52:35 scott@TEST0910> select count(*) from test10;
?
? COUNT(*)
----------
???????? 0
3、使用闪回查询
11:54:25 scott@TEST0910>
select * from test10 as of timestamp to_timestamp('2013-09-23 11:52:06','yyyy-mm-dd hh24:mi:ss');
?
???? EMPNO ENAME????? JOB????????????? MGR HIREDATE???????? SAL?????? COMM???? DEPTNO
---------- ---------- --------- ---------- --------- ---------- ---------- ----------
????? 7369 SMITH????? CLERK?????????? 7902 17-DEC-80??????? 800??????????????????? 20
????? 7499 ALLEN????? SALESMAN??????? 7698 20-FEB-81?????? 1600??????? 300???????? 30
????? 7521 WARD?????? SALESMAN??????? 7698 22-FEB-81?????? 1250??????? 500???????? 30
????? 7566 JONES????? MANAGER???????? 7839 02-APR-81?????? 2975??????????????????? 20
????? 7654 MARTIN???? SALESMAN??????? 7698 28-SEP-81?????? 1250?????? 1400???????? 30
????? 7698 BLAKE????? MANAGER???????? 7839 01-MAY-81?????? 2850??????????????????? 30
????? 7782 CLARK????? MANAGER???????? 7839 09-JUN-81?????? 2450??????????????????? 10
????? 7788 SCOTT????? ANALYST???????? 7566 19-APR-87?????? 3000??????????????????? 20
????? 7839 KING?????? PRESIDENT??????????? 17-NOV-81?????? 5000??????????????????? 10
????? 7844 TURNER???? SALESMAN??????? 7698 08-SEP-81?????? 1500????????? 0???????? 30
????? 7876 ADAMS????? CLERK?????????? 7788 23-MAY-87?????? 1100??????????????????? 20
????? 7900 JAMES????? CLERK?????????? 7698 03-DEC-81??????? 950??????????????????? 30
????? 7902 FORD?????? ANALYST???????? 7566 03-DEC-81?????? 3000??????????????????? 20
????? 7934 MILLER???? CLERK?????????? 7782 23-JAN-82?????? 1300??????????????????? 10
?
14 rows selected.
?
4、插入闪回查询的结果
11:54:44 scott@TEST0910>
insert into test10 select * from test10 as of timestamp to_timestamp('2013-09-23 11:52:06','yyyy-mm-dd hh24:mi:ss');
?
14 rows created.
?
11:55:02 scott@TEST0910> commit;
?
Commit complete.
?
11:55:30 scott@TEST0910> select count(*) from test10;
?
? COUNT(*)
----------
??????? 14
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