flashback table实验（基于undo数据）
发布时间：2020-12-15 17:55:08 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 1、查询原数据 sys@TEST0910 select count(*) from test10; ? ? COUNT(*) ---------- ??????? 14 ? 1 row selected. 2、查询数据库当前scn号，稍后作为恢复参考 sys@TEST0910 select checkpoin
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开启闪回：http://www.voidcn.com/article/p-okbbpchw-bbu.html
1、查询原数据
sys@TEST0910> select count(*) from test10;
?
? COUNT(*)
----------
??????? 14
?
1 row selected.
2、查询数据库当前scn号，稍后作为恢复参考
sys@TEST0910> select checkpoint_change# from v$database;
?
CHECKPOINT_CHANGE#
------------------
?????????? 1952615
?
1 row selected.
3、误操作
sys@TEST0910> delete from scott.test10;
?
14 rows deleted.
?
sys@TEST0910> commit;
?
Commit complete.
?
4、根据之前的scn号使用undo数据闪回查询
sys@TEST0910> select * from scott.test10 as of scn 1952615;
?
???? 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.
?
5、将数据还原
可以插入回去，如闪回查询那样：
insert into test10 select * from scott.test10 as of scn 1952615;
另外一种，可以用闪回表的方式：
flashback table scott.test10 to scn 1952615;
注意，闪回表时要开启 row movement，不然要报错。
?
sys@TEST0910> flashback table scott.test10 to scn 1952615;
flashback table scott.test10 to scn 1952615
????????????????????? *
ERROR at line 1:
ORA-08189: cannot flashback the table because row movement is not enabled
?
?
sys@TEST0910> alter table scott.test10 enable row movement;
?
Table altered.
?
sys@TEST0910>
flashback table scott.test10 to scn 1952615;
?
Flashback complete.
?
sys@TEST0910> select count(*) from scott.test10;
?
? COUNT(*)
----------
??????? 14
?
1 row selected.
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