cmc-sales/app/config/database_stg.php

<?php

  class DATABASE_CONFIG {

    var $default = array(
      'driver' => 'mysql',
      'persistent' => false,
      'host' => 'db-staging',
      'login' => 'cmc_staging',
      'password' => 'staging_password',
      'database' => 'cmc_staging',
      'prefix' => '',
    );
    }