DATABASE START UP MODES( STARTUP - UPGRADE - RESTRICT - FORCE - QUIET)

STARTUP UPGRADE
-------------------------------
Starts the database in OPEN UPGRADE mode and sets system initialization parameters to specific values required to enable database upgrade scripts to be run. UPGRADE should only be used when a database is first started with a new version of the Oracle Database Server.


STARTUP RESTRICT
-----------------------------
Only enables Oracle Database users with the RESTRICTED SESSION system privilege to connect to the database. Later, you can use the ALTER SYSTEM command to disable the restricted session feature.

STARTUP FORCE
------------------------

Shuts down the current Oracle Database instance (if it is running) with SHUTDOWN mode ABORT, before restarting it. If the current instance is running and FORCE is not specified, an error results. FORCE is useful while debugging and under abnormal circumstances. It should not normally be used.

SQL> STARTUP FORCE;
ORACLE instance started.

Total System Global Area  805306368 bytes
Fixed Size                  1289996 bytes
Variable Size             218104052 bytes
Database Buffers          583008256 bytes
Redo Buffers                2904064 bytes
Database mounted.
Database opened.
SQL> SELECT OPEN_MODE FROM V$DATABASE;

OPEN_MODE
----------
READ WRITE

SQL> STARTUP FORCE;
ORACLE instance started.

Total System Global Area  805306368 bytes
Fixed Size                  1289996 bytes
Variable Size             218104052 bytes
Database Buffers          583008256 bytes
Redo Buffers                2904064 bytes
Database mounted.
Database opened.

SQL> STARTUP

ORA-01081: cannot start already-running ORACLE - shut it down first


STARTUP QUIET
-----------------------
Suppresses the display of System Global Area information for the starting instance.

SQL> STARTUP QUIET;
ORACLE instance started.
Database mounted.
Database opened.


Thank You!