ORA-00000: normal, successful completion

ORA-00000: normal, successful completion

This error may occur in many circumstances you need to check environment variables:
$ORACLE_HOME
$ORACLE_BASE
$ORACLE_SID
also check /etc/hosts file it must contains correct hostname and ip.
example:

[oracle@oel6 ~]$ sqlplus / as sysdba

SQL*Plus: Release 11.2.0.3.0 Production on Mon Jan 1 9:12:17 2014

Copyright (c) 1982, 2011, Oracle.  All rights reserved.

Connected.
SQL> startup;
ORA-01012: not logged on
SQL> shutdown immediate;
ORA-00000: normal, successful completion
SQL> shutdown abort;
ORACLE instance shut down.
SQL> startup;
ORA-00000: normal, successful completion


After that i checked environment variables:
[oracle@server1 ~]$ echo $ORACLE_BASE
/u01/app/oracle
[oracle@server1 ~]$ echo $ORACLE_HOME
/u01/app/oracle/product/11.2.0/db_1
[oracle@server1 ~]$ echo $ORACLE_SID
prim

Then i checked /etc/hosts
cat /etc/hosts
#192.168.2.102   server1.soumya.com      server1

So i found the issue. The hostname and ip was commented inside /etc/hosts file.

Then i started up the database and everything was right.
SQL> startup
ORACLE instance started.

Total System Global Area  413372416 bytes
Fixed Size                  2213896 bytes
Variable Size             331352056 bytes
Database Buffers           75497472 bytes
Redo Buffers                4308992 bytes
Database mounted.
Database opened.


P.S.Generally ORA-00000 comes under "Oracle Database Server Messages". These messages are generated by the Oracle database server when running any Oracle program.