ORACLE 利用SCN恢复误delete的表

--kg是误删除的表

SQL> select count(*) from kg;

  COUNT(*)

----------

    820861

SQL> delete from kg;

820861 rows deleted

SQL> commit;

Commit complete

SQL> select count(*) from kg;

  COUNT(*)

----------

         0

SQL> rollback;

Rollback complete

SQL> select count(*) from kg;

  COUNT(*)

----------

         0

--kg被删除且已经提交。

--查询此时数据库的SCN

SQL> select dbms_flashback.get_system_change_number from dual;

GET_SYSTEM_CHANGE_NUMBER

------------------------

                 4915780

SQL> select count(*) from kg as of scn 4915780;

  COUNT(*)

----------

         0

--创建表howard存放数据库的SCN

SQL> create table howard(count int,scn int);

Table created

SQL> DECLARE

     i INT:=4915600;

     BEGIN

        FOR i IN 4915600..4915782 LOOP

          INSERT INTO howard( SCN) VALUES (i );

          UPDATE howard SET COUNT =(SELECT COUNT(*) FROM kg AS OF SCN i) WHERE SCN= i;

        END LOOP ;

     END ;

     /

SQL> SELECT * FROM howard

SQL> /

                                  COUNT                                     SCN

--------------------------------------- ---------------------------------------

                                 820861                                 4915704

                                 820861                                 4915705

                                 820861                                 4915706

                                      0                                 4915707

                                      0                                 4915708

                                      0                                 4915709

--得到删除前数据库的SCN，恢复表数据

SQL>  select count(*) from kg  as of scn 4915706;

  COUNT(*)

----------

    820861

SQL> select count(*) from kg  as of scn 4915707;

  COUNT(*)

----------

         0

SQL> insert into kg select * from kg as of scn 4915706;

820861 rows inserted

SQL> drop table howard;

Table dropped

SQL> commit;

Commit complete