when we try to connect our programme with oracle it is giving error

Question

when i try to connect our programme with oracle with this command

sqlplus crbt/crbt@crbt_new here crbt is the username and crbt_new is the password.

it is giving error this

SQL*Plus: Release 9.2.0.4.0 - Production on Tue Jan 4 10:32:42 2011
Copyright (c) 1982, 2002, Oracle Corporation.  All rights reserved.
ERROR:ORA-12541: TNS:no listener

So please tell me where this is wrong

Answer 1

Below are the possibilities for this:

1) Listener might be down

2) When database is not up, 'TNS: no listener' error appears

3) If the TNS entries are not correct.

Ex: The TNS entry of crbt_new database might have the port number mentioned as 1531, but in real the Database would be listening on port 1521