Create a new database manually

1) su - oracle
	
2) create a oradata directory structure & for trace directories
	mkdir -p /u01/oradata/mahi
	mkdir -p /u01/app/oracle/admin/mahi
	cd /u01/app/oracle/admin/mahi
	mkdir bdump cdump udump pfile adump
3) Create parameter file manually with mandatory parameters 

vi initmahi.ora
	
	*.user_dump_dest='/u01/app/oracle/admin/mahi/udump'
	*.core_dump_dest='/u01/app/oracle/admin/mahi/cdump'
	*.background_dump_dest='/u01/app/oracle/admin/mahi/bdump'
        *.diagnostic_dest=/u01/app/oracle/admin/diag
	*.compatible='11.2.0.0.0'
	*.control_files=('/u01/oradata/mahi/control01.ctl')
	*.db_block_size=8192
	*.db_file_multiblock_read_count=16
	*.db_name='mahi'
	*.fast_start_mttr_target=600
	*.instance_name='mahi'
	*.job_queue_processes=10
	*.workarea_size_policy='AUTO'
	*.pga_aggregate_target=25M
	*.remote_login_passwordfile='EXCLUSIVE'
	*.timed_statistics=TRUE
	*.undo_management='AUTO'
	*.undo_tablespace='UNDOTBS1'
	*.undo_retention=3600
	*.sga_max_size=250m
	*.sga_target=250m
	*.db_file_recovery_dest='/u01/oradata/backups/'
	*.db_file_recovery_dest_size=2g
	*.processes=500 
	*.sessions=300

Note: the parameter file name format must be init<sid>.ora, here i am going to create a database name as mahi and used initmahi.ora
Remember, this parameter file should be placed in $ORACLE_HOME/dbs
The order of the pfile read by oracle is
it will read spfile if its there in $ORACLE_HOME/dbs
if not read pfile if its there in $ORACLE_HOME/dbs
if not read the pfile given in prompt like startup pfile=''

4) set oracle sid
	export ORACLE_SID=mahi
Note teh oracle_sid is case sensitive

5) set oracle home 
	export ORACLE_HOME=/u01/app/oracle/product/11.2.0/db_1

6) set path
	export PATH=/u01/app/oracle/product/11.2.0/db_1:$PATH

5) create a password file
	$ORACLE_HOME/bin/orapwd file=$ORACLE_HOME/dbs/pwdmahi.ora password=oracle entries=5

6) start the instance
	sqlplus / as sysdba
	startup nomount


7) in SQLPLUS sq
sqlplus
	create database mahi
	MAXINSTANCES 8   
	MAXLOGHISTORY 100   
	MAXLOGFILES 64   
	MAXLOGMEMBERS 3   
	MAXDATAFILES 150	
	logfile group 1 ('/u01/oradata/mahi/redo1.log') size 100M,
            group 2 ('/u01/oradata/mahi/redo2.log') size 100M,
            group 3 ('/u01/oradata/mahi/redo3.log') size 100M
	character set WE8ISO8859P1
	national character set utf8
	datafile '/u01/oradata/mahi/system.dbf' size 500M autoextend on next 10M maxsize unlimited extent management local
	sysaux datafile '/u01/oradata/mahi/sysaux.dbf' size 100M autoextend on next 10M maxsize unlimited
	undo tablespace undotbs1 datafile '/u01/oradata/mahi/undotbs1.dbf' size 100M
	default temporary tablespace temp tempfile '/u01/oradata/mahi/temp01.dbf' size 100M;

8) Create dictionary views
	Sqlplus / as sysdba
	@?/sqlplus/rdbms/admin/catalog.sql
	@?/sqlplus/rdbms/admin/cataproc.sql
	@?/sqlplus/rdbms/lib/pupbld.sql

9) Shutdown the datasbe and restart
	sqlplus / as sysdba
	shut immediate
	exit

	sqlplus / as sysdba
	startup
	exit

10) compile invalids
	@?/rdbms/admin/utlrp.sql 


11) create a users tablespace
	create tablespace users datafile '/u01/oradata/mahi/users.dbf' size 100m maxsize unlimited extent management local segment space management auto;

12) Create network files
	cd /u01/app/oracle/product/11.2.0/db_1/network/admin
	vi tnsnames.ora
	
	DEMO =   
	(DESCRIPTION =   
	(ADDRESS = (PROTOCOL = TCP)(HOST = mahish.localdomain)(PORT = 1521))   
	(CONNECT_DATA =   
	(SERVER = DEDICATED)   
	(SERVICE_NAME = mahi)   
	)   
	) 

	
	in Listener.ora in sid_list

      (SID_DESC =
      (SID_NAME = mahi)
      (ORACLE_HOME = /u01/app/oracle/product/11.2.0/db_1)
       )

13) Start the listener
	
14) add entry in oratab