Hi Sandeep,
You will want to make sure that all of the following are set to talk to your database in config.php
Your config.php file is in the root directory that holds the code for your moodle site.
find the following lines and:
$CFG->dbhost = 'xxxxxx'; //replace the x's with either localhost of the ip address of the database server
$CFG->dbname = 'yyyyyy'; //replace the y's with the name of the moodle database on your database server
$CFG->dbuser = 'aaaaa'; //replace the a's with the username of the database user
$CFG->dbpass = 'bbbbbb'; //replace the b's with the new password you set for the database user