如果你在工作中误删除了一部分重要的数据，并且已经提交，当你需要恢复数据的时候，你可以登陆到数据库上仔细查看，如果是Oracle9iR2，你可以首先尝试使用flashback query闪回数据。

◆第一步：确认数据库的SCN变化:

以下为引用的内容： SQL> col fscn for 9999999999999999999 SQL> col nscn for 9999999999999999999 SQL> select name,FIRST_CHANGE# fscn,NEXT_CHANGE# nscn,FIRST_TIME from v$archived_log; ................... NAME                               FSCN       NSCN FIRST_TIME ----------------------------     ---------   ------------------- /mwarch/oracle/1_52413.dbf     12929941968   12929942881 2005-06-22 14:38:28 /mwarch/oracle/1_52414.dbf     12929942881   12929943706 2005-06-22 14:38:32 /mwarch/oracle/1_52415.dbf     12929943706   12929944623 2005-06-22 14:38:35 /mwarch/oracle/1_52416.dbf     12929944623   12929945392 2005-06-22 14:38:38 /mwarch/oracle/1_52417.dbf     12929945392   12929945888 2005-06-22 14:38:41 /mwarch/oracle/1_52418.dbf     12929945888   12929945965 2005-06-22 14:38:44 /mwarch/oracle/1_52419.dbf     12929945965   12929948945 2005-06-22 14:38:45 /mwarch/oracle/1_52420.dbf     12929948945   12929949904 2005-06-22 14:46:05 /mwarch/oracle/1_52421.dbf     12929949904   12929950854 2005-06-22 14:46:08 /mwarch/oracle/1_52422.dbf     12929950854   12929951751 2005-06-22 14:46:11 /mwarch/oracle/1_52423.dbf     12929951751   12929952587 2005-06-22 14:46:14 ................... /mwarch/oracle/1_52498.dbf     12930138975   12930139212 2005-06-22 15:55:57 /mwarch/oracle/1_52499.dbf     12930139212   12930139446 2005-06-22 15:55:59 /mwarch/oracle/1_52500.dbf     12930139446   12930139682 2005-06-22 15:56:00 NAME                             FSCN           NSCN FIRST_TIME -------------------------  -------------       ----------- /mwarch/oracle/1_52501.dbf     12930139682    12930139915 2005-06-22 15:56:02 /mwarch/oracle/1_52502.dbf     12930139915    12930140149 2005-06-22 15:56:03 /mwarch/oracle/1_52503.dbf     12930140149    12930140379 2005-06-22 15:56:05 /mwarch/oracle/1_52504.dbf     12930140379    12930140610 2005-06-22 15:56:05 /mwarch/oracle/1_52505.dbf     12930140610    12930140845 2005-06-22 15:56:07 14811 rows selected.

◆此时的SCN为：

以下为引用的内容： SQL> select dbms_flashback. get_system_change_number fscn from dual;                 FSCN --------------------          12930142214

◆此时使用应用用户尝试闪回

以下为引用的内容： SQL> connect username/password Connected.

◆现有的数据:

以下为引用的内容： SQL> select count(*) from hs_passport;   COUNT(*) ----------     851998

◆创建恢复表

以下为引用的内容： SQL> create table hs_passport_recov as select * from hs_passport where 1=0; Table created.

◆此处选择SCN向前恢复

以下为引用的内容： SQL> select count(*) from hs_passport as of scn 12929970422;   COUNT(*) ----------     861686

◆尝试多个SCN，获取最佳值（注释：如果可以得知具体时间，那样则可以获得准确的数据闪回）

以下为引用的内容： SQL> select count(*) from hs_passport as of scn &scn; Enter value for scn: 12929941968 old   1: select count(*) from hs_passport as of scn &scn new   1: select count(*) from hs_passport as of scn 12929941968   COUNT(*) ----------     861684 SQL> / Enter value for scn: 12927633776 old   1: select count(*) from hs_passport as of scn &scn new   1: select count(*) from hs_passport as of scn 12927633776 select count(*) from hs_passport as of scn 12927633776                     * ERROR at line 1: ORA-01466: unable to read data - table definition has changed SQL> / Enter value for scn: 12929928784 old   1: select count(*) from hs_passport as of scn &scn new   1: select count(*) from hs_passport as of scn 12929928784   COUNT(*) ----------     825110 SQL> / Enter value for scn: 12928000000 old   1: select count(*) from hs_passport as of scn &scn new   1: select count(*) from hs_passport as of scn 12928000000 select count(*) from hs_passport as of scn 12928000000                      * ERROR at line 1: ORA-01466: unable to read data - table definition has changed

◆注意：最后选择恢复到SCN为12929941968的时间点

以下为引用的内容： SQL> insert into hs_passport_recov select * from hs_passport as of scn 12929941968; 861684 rows created. SQL> commit; Commit complete.

注释：至此，则可以满足需要，找回误删除的部分数据，闪回恢复成功。

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