Init a second database in codeigniter by a helper function - codeigniter

Question

In my site are different modules, each has its own datatable.
So now I'm not sure which is the best way to connect these modules in the best way.
My idea is to create a helper function, which tests if is a database-connection is available or not. If not, the helper should init the database and make the database for queries available in the controller and models.
In the documentation of Codeigniter I've only found information about multiple database setup - I cannot find an example for do that with a kind of dynamic helper.
Maybe someone can help me a step further?

Answer 1

What you can do is set session of your db_name, db_user and db_pass (if user and pass are different for each db_name). In order to reuse the dynamic db without always passing the access.
Here is an implementation:
Helper:
if (!function_exists('get_dynamic_db')){
function get_dynamic_db()
{
$CI =& get_instance();
$db = $CI->session->user_data('other_db');
$user = $CI->session->user_data('other_db_user');
$pass = $CI->session->user_data('other_db_pass');
$config_app = array(
'dsn' => '',
'hostname' => 'localhost',
'username' => $user,
'password' => $pass,
'database' => $db,
'dbdriver' => 'mysqli',
'dbprefix' => '',
'pconnect' => FALSE,
'db_debug' => (ENVIRONMENT !== 'production'),
'cache_on' => FALSE,
'cachedir' => '',
'char_set' => 'utf8',
'dbcollat' => 'utf8_general_ci',
'swap_pre' => '',
'encrypt' => FALSE,
'compress' => FALSE,
'stricton' => FALSE,
'failover' => array(),
'save_queries' => TRUE
);
return $CI->load->database($config_app,TRUE);
}
}
Model:
Class DD_model extends CI_Model {
var $dynamic_db;
public function __construct() {
$this->load->database(); // default db
$this->dynamic_db = get_dynamic_db(); // dynamic db
}
public function ping_server_db()
{
$this->dynamic_db->from('some_table');
$query = $dynamic_db->get();
return $query->row() ? true : false;
}
}
Controller:
public function select_db($db_name)
{
$this->session->set_userdata(array('other_db' => $db_name, 'other_db_user' => 'user', 'other_db_pass' => 'pass'));
$dynamic_db = $this->DD_model->ping_server_db();
if (!$dynamic_db) {
$this->session->unset_userdata('other_db');
return false;
}
}
With this, you can then use get_dynamic_db(); in all your models to query from dynamic db