Database creation
Database can created in three different ways in oracle
1)DBCA(GUI interface creation)
2)OMF(Oracle Managed Files)
3)Manual Creation
Oracle supports some tools to create a database.But, here we are manually creating the database.
Generally the home directory for oracle software is ORACLE_HOME.Different oracle versions are stored in this oracle_home directory
Manual Database creation:
Steps to create database manually
Step 1: Set the environmental variables
- environmental variables are nothing but a executable file
 
- go to .bash_profile directory and set some environmental variables in that directory as follows
 
     export  ORACLE_SID    =  <sid name> 
     export    PATH                 =$ORACLE_HOME/bin:$PATH:.
         :wq!-------------save file 
- set the above environmental variables in .bash_profile directory and execute the file as follows
 
    $echo $ORACLE_HOME------>to display contents in ORACLE_HOME
Step 2: Creating pfile(parameter file)   
$ cd ORACLE_HOME/dbs----->move to dbs directory where it is located in ORACLE_HOME
$ ls------>list all file in that directory
$ cp init.ora  init$ORACLE_SID.ora-------->copy init.ora file to init<SID NAME>.ora
$vi init<SID NAME>.ora--------------->open copied file and make changes as follows
  db_name=<SID NAME>
  control_file=/disk1/oradata/test_database/control.ctl------->create this directory path before editing this file
 diagnostic_dest=/disk1/oradata/test_database------->create directory path before editing this file
:wq!-------- >save file 
Step 3: Script for creating database
- Make a folder with name createdatabse.sql in /home location
 - Now enter into that folder and write script as follows
 
     create database <SID NAME>
    datafile '/disk1/oradata/test_database/system.dbf ' size 170m autoextended on
    sysaux datafile  '/disk1/oradata/test_database/sysaux.dbf ' size 70m autoextended on
    undo tablespace  <Tablespace name>
   datafile  '/disk1/oradata/test_database/<tablespace name>.dbf ' size 30m 
   default tablespace <Tablespace name>
   datafile   '/disk1/oradata/test_database/<tablespace name>.dbf ' size 40m
   default temporary tablespace<Tablespace name>
   tempfile  '/disk1/oradata/test_database/<tablespace name>.dbf ' size 30m
   logfile
   group 1( '/disk1/oradata/test_database/redo1.log') size 4m,
   group 2( '/disk1/oradata/test_database/redo2.log') size 4m
   controlfile reuse;
:wq!------------->save the file
Step 4 : Script creating for base tables
- Make a folder with name basetables.sql in /home location
 - Now enter into that folder and write script as follows
 
@$<path where oracle software is located>ORACLE_HOME/rdbms/admin/catproc.sql------>(this is to create packages and PL/SQL procedures)
conn system/manager------>to connect as admin user
@$<path where oracle software is located>ORACLE_HOME/sqlplus/admin/pupbld.sql ------->(to start sql*plus to all users)
Step 5 : connect to oracle database as follows
$ sqlplus / as sysdba-----> to connect to oracle database
sys> startup nomount  ---- - > to connect database in nomount state
sys> @createdatabase.sql ------ > run the script to create database
sys> @createbasetables.sql ------> run the script to create base tables
sys> select instance_name,status from v$instance;------>check the status after creating the databse