Shut Down types and Detail explanation

Shutting down Means==> Making the database is unavailable for use

Shutdown will work in three stages:

First stage of shutdown:

Database closed
Check point may be performed when proper shutdown is done
Datafiles and redo log files are closed
Second stage of shutdown:
Dismount the database
Control file is closed
Third stage of shutdown:
Oracle Instance shutdown

Proper shutdown have three types of  Shutdown's:

shutdown Normal:

-Waits for all users who are connected to disconnect
-will not allow new connections to be created
-Will perform a checkpoint and write all the dirty buffers in the database
buffer cache to the datafiles ==DB will be in an consistent state

shutdown immediate:

-Does not wait for all users to disconnect
-Will disconnect all users and rollback their ongoing transactions
-Will not allow new connections to be created
-will perform a checkpoint and write all the dirty buffers in the DB
buffer cache to the datafile ===DB will be in an consistent state

Shutdown transactional:

-Does not wait for all users to disconnect
-Will disconnect a users when their current transaction is completed
-Will not allow new connections to be created
-Will perform a checkpoint and write all the dirty buffers in the DB buffer cache to the
datafiles==DB will be in an consistent state

Improper Shutdown:

Shutdown abort:

-Does not wait for all users to disconnect
-Terminates the current instance forcefully
-Will not allow new conncetions to be created
-Will NOT perform a checkpoint and does not write all the dirty buffers in the DB
buffer cache to the datafiles ==DB will be in an inconsisteant state
-SMON background process will perform instance recovery on next startup