Way to create a New database In Oracle

Any person can create a oracle database in two fashion.
1. Using DBCA ( Database Configuration Assistant )
2. Manually

1. Using DBCA: It is a utility provided by oracle and it is present in the $ORACLE_HOME/bin directory. It is a GUI utility and OUI ( Oracle Universal Installer ) installs the software it's normally run this DBCA to create the database.
You can also explicitely run this utility to create database.

2. Manually: You can create database manully using scripts. I am giving an example of creating database using scripts. For this you have to set some veriables.

First run the following command

sqlplus /nolog

Then the following command one after another.

CONNECT SYS AS SYSDBA;
ALTER SYSTEM SET DB_CREATE_FILE_DEST = ‘/user1/oracle/’;
ALTER SYSTEM SET DB_CREATE_ONLINE_LOG_DEST_1=’ /user2/oracle/’;
ALTER SYSTEM SET DB_CREATE_ONLINE_LOG_DEST_2=’ /user3/oracle/’;


Then run the following command or script

CREATE DATABASE oradba CONTROLFILE REUSE
LOGFILE
GROUP 1 ('/oracle/oradba/log01a.log', '/oracle/oradba/log01b.log') size 50M,
GROUP 2 ('/oracle/oradba/log02a.log', '/oracle/oradba/log02b.log') size 50M,
GROUP 3 ('/oracle/oradba/log03a.log', '/oracle/oradba/log03b.log') size 50M
DATAFILE
'/oracle/oradba/system.dbf' 250M
AUTOEXTEND ON MAXSIZE 500M
UNDO TABLESPACE undots
DATAFILE '/oracle/oradba/undots.dbf' 50M
DEFAULT TEMPORARY TABLESPACE temp
TEMPFILE '/oracle/oradba/temp.dbf' size 75M
EXTENT MANAGEMENT LOCAL
CHARACTER SET US7ASCII
MAXLOGFILES 10
MAXLOGMEMBERS 10
MAXLOGHISTORY 1
MAXDATAFILES 500;

The database named oradba will be created.