In the previous post about setting project environment setting http://ganeshhs.com/php/php-configuring-project-environment-using-ini-file , zend config plays a vital role in initializing the environment variables and by default, configuration data made available through Zend_Config are read-only.

Lets write the ini configuration file application/config.ini

[staging]
db.adapter 	    = PDO_MYSQL
db.config.host 	    = localhost
db.config.username  = mysql_user
db.config.password  = mysql_password
db.config.dbname    = mysql_database
show_errors         = true

[production]
db.adapter 	    = PDO_MYSQL
db.config.host 	    = mysql_host_name
db.config.username  = mysql_user
db.config.password  = mysql_password
show_errors         = false

Lets add the following code in boot strap file public/index.php

<?php

require_once 'Zend/Config/Ini.php';

$config = new Zend_Config_Ini('/path/to/config.ini', 'staging');
// in our project we will be using path application/config.ini

// Try printing host name
echo "Host Name: ".$config->db->config->host;
?>

Reference Links:
http://ganeshhs.com/php/php-configuring-project-environment-using-ini-file
http://framework.zend.com/manual/en/zend.config.theory_of_operation.html