Use different db name in db connectivity file?

[eluser]Zeeshan Rasool[/eluser]
Hello all,
Can we make this connection changeable so that we change db name each time to make a connection.

Code:

$db['default']['hostname'] = "localhost";
$db['default']['username'] = "root";
$db['default']['password'] = "";
$db['default']['database'] = "db_name";
$db['default']['dbdriver'] = "mysql";
$db['default']['dbprefix'] = "";
$db['default']['pconnect'] = TRUE;
$db['default']['db_debug'] = TRUE;
$db['default']['cache_on'] = FALSE;
$db['default']['cachedir'] = "";
$db['default']['char_set'] = "utf8";

[eluser]TheFuzzy0ne[/eluser]
Sorry, I don't understand the question.