PLS-00201:identifier 'DBMS_FLASHBA...

在使用PL/SQL包dbms_flashback做闪回查询时，不能直接使用‘SYS’用户来调用：

SQL> exec dbms_flashback.enable_at_time(systimestamp-interval '15' minute);

BEGIN dbms_flashback.enable_at_time(systimestamp-interval '15' minute); END;

*

ERROR at line 1:

ORA-08185: Flashback not supported for user SYS

ORA-06512: at "SYS.DBMS_FLASHBACK", line 3

ORA-06512: at line 1

切换成需要进行闪回查询的普通用户，不过在此之前需要对此用户进行授权。如不授权会出现如下错误：

SQL> exec dbms_flashback.enable_at_time(systimestamp-interval '15' minute);

BEGIN dbms_flashback.enable_at_time(systimestamp-interval '15' minute); END;

      *

ERROR at line 1:

ORA-06550: line 1, column 7:

PLS-00201: identifier 'DBMS_FLASHBACK' must be declared

ORA-06550: line 1, column 7:

PL/SQL: Statement ignored

授权：

SQL> conn / as sysdba

Connected.

SQL> grant execute on dbms_flashback to scotto;

Grant succeeded.

SQL> conn scotto/scotto;

Connected.

SQL> exec dbms_flashback.enable_at_time(systimestamp - interval '15' minute);

PL/SQL procedure successfully completed.

SQL> 

SQL> exec dbms_flashback.disable;

PL/SQL procedure successfully completed.

注意在闪回会话模式中是不能执行写入操作的（包括DDL和update\delete等）

SQL> update test set username='ha0' where username='ha1';
update test set username='ha0' where username='ha1'
       *
ERROR at line 1:
ORA-08182: operation not supported while in Flashback mode