STARTUP AND SHUTDOWN IN ORACLE

Startup and Shutdown Option in Oracle:-

startup nomount
-it ill read the parameter file(spfile/pfile) and check the spelling and directories if it ok
-It Will up the instance and Bg Process.
-Then the database Starts that information writes to alertlog file.

startup Mount
-To mount the database ,instance read the controlfile physically present or Not.
-And open the controlfiles read the databasefile and logfile path.

startup open
-it check datafile's and logfile physically present or not.
-it read controlfile header and datafile header check any recovery(scn check controlfile heard and datafile header same).
-And start the database server process.
-check unod rollback activities
-open logfile to use archive redo's

SHUTING DOWN OPERATIONS