Getting Started - Oracle RMAN for Absolute Beginners - page 10

This startup process is depicted graphically in Figure 1-1 .

Figure 1-1. Phases of Oracle startup

When you issue a STARTUP statement without any parameters, Oracle automatically steps through the three
startup phases (nomount, mount, open). In most cases, you will issue a STARTUP statement with no parameters to start
your database. In many RMAN backup and recovery scenarios, you'll issue a STARTUP MOUNT to place your database in
mount mode (instance started and control files opened). Table 1-2 describes the meanings of parameters that you can
use with the database STARTUP statement.

Table 1-2. Parameters Available with the STARTUP Command

Parameter Meaning

FORCE

Shuts down the instance with ABORT before restarting it; useful for troubleshooting startup
issues

RESTRICT

Only allows users with the RESTRICTED SESSION privilege to connect to the database

PFILE

Specifies the client parameter file to be used when starting the instance

QUIET

Suppresses the display of SGA information when starting the instance

NOMOUNT

Starts background processes and allocates memory; doesn't read control files

MOUNT

Starts background processes, allocates memory, and reads control files

OPEN

Starts background processes, allocates memory, reads control files, and opens online redo
logs and data files

OPEN RECOVER

Attempts media recovery before opening the database

OPEN READ ONLY

Opens the database in read-only mode

UPGRADE

Used when upgrading a database

DOWNGRADE

Used when downgrading a database