Translating Oracle Document--SYSDBA and Sysoper system permissions

SYSDBA and Sysoper are administrative permissions that are performed by the user to perform advanced administrative operations such as creating an on/off backup/restore database.
SYSDBA system permissions are for database administrators who want to give full authorization
Sysoper system permissions allow a user to perform basic operational tasks, but are not able to view user data.

SYSDBA and Sysoper system permissions allow access to the DB instance even when the database is not open. The control of these permissions is therefore completely outside the database itself,
This control allows a person who is granted one of these permissions to connect to the DB instance to open the database.

You can also assume that Sysdba and Sysoper permissions are the types of connections that allow you to perform several database operations that cannot be granted in other ways. For example: If you have SYSDBA permissions, then you can
Connect to the database using as SYSDBA.

SYS user is automatically granted the SYSDBA permission during installation. When you log in as user sys, you must connect the user as Sysdba or sysoper.
The connection as SYSDBA user contains SYSDBA permissions, and the connection as Sysoper contains Sysoper permissions. OEMDC does not allow you to log on as user Sys but is not connected as SYSDBA or Sysoper

When you connect as SYSDBA or Sysoper permissions, you connect a default mode, and the non-specified pattern is usually associated with your user name. For example: SYSDBA this mode is SYS
Sysoper mode is public.

Caution:
When you connect as user sys, you have unrestricted permissions on the Data Catalog table. Make sure you don't modify any catalog data tables.

See Also:
Oracle Database Administrator ' s Guide for operations that grant SYSDBA and Sysoper permissions.

Translate Oracle Document--SYSDBA and Sysoper system permissions