ORA-28009: connection as SYS should be as SYSDBA or SYSOPER

You are getting error, ORA-28009: connection as SYS should be as SYSDBA or SYSOPER while logging to the Oracle as SYS user.

>sqlplus

SQL*Plus: Release 10.2.0.1.0 - Production on Tue Jan 7 19:16:36 2014

Copyright (c) 1982, 2005, Oracle.  All rights reserved.

Enter user-name: SYS
Enter password:
ERROR:
ORA-28009: connection as SYS should be as SYSDBA or SYSOPER

Solution

The error is generated if the parameter O7_DICTIONARY_ACCESSIBILITY is set to FALSE. But, Oracle not recommended us to set the value as TRUE.

SQL> show parameter O7_DICTIONARY_ACCESSIBILITY

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
O7_DICTIONARY_ACCESSIBILITY          boolean     FALSE

So, to eliminate the error, you need to use the following command when connecting as SYS user.