Codeigniter using sessions in Database class
<p>I need your help in codeigniter project. I want to use session to dynamic change data base on databse file in config folder. 
I do $db['default']['database'] = $_SESSION['db_name'], in config file but dont work.
The login page Should check which other database access to do login.</p>

<p>Is it possible to change the connection before selecting the database?</p>

<p>Login page</p>

<pre><code>public function login(){
if(!$this-&gt;session-&gt;userdata('id_funcionario') || !$this-&gt;session-&gt;userdata('logado')){ 

    $this-&gt;db-&gt;database= "test";
    $this-&gt;session-&gt;destroy();
    $subdomain = $_SERVER['HTTP_HOST'];  
    $this-&gt;db-&gt;select("database");
    $this-&gt;db-&gt;where("subdomain", $subdomain);
    $access = $this-&gt;db-&gt;get("table")-&gt;row();
    $this-&gt;session-&gt;set_userdata("database", $access-&gt;database);
    $this-&gt;load-&gt;view('/geral/login'); 

}else{
    $url = base_url('home');
    header("Location: $url ");

}
</code></pre>

<p>}</p>

<p>The login page works!</p>

<p>The data are send for AJAX to:</p>

<pre><code>&lt;?php if(!defined('BASEPATH')) exit('No direct script access allowed');
class Ajax extends CI_Controller {

    public function __construct(){
        parent::__construct();
        $this-&gt;load-&gt;helper('url');
        $this-&gt;load-&gt;helper('html');
        $this-&gt;load-&gt;library('session');

    }
public function toLog()
    { 
        $email = $this-&gt;input-&gt;post('email');
        $pass= md5($this-&gt;input-&gt;post('pass'));

        $this-&gt;db-&gt;database = $this-&gt;session-&gt;userdata('database');
        $this-&gt;db-&gt;select('*');
        $this-&gt;db-&gt;from('users');
        $this-&gt;db-&gt;where('usu_email',$email);
        $this-&gt;db-&gt;where('usu_pass',$pass);
        $usuario = $this-&gt;db-&gt;get()-&gt;result();
</code></pre>

<p>But I do not know how to change the name of the database on time of the query. I have tried and it remains unchanged.</p>

<pre><code>&lt;?php  if ( ! defined('BASEPATH')) exit('No direct script access allowed');


/**
 * Database Driver Class
 *
 * This is the platform-independent base DB implementation class.
 * This class will not be called directly. Rather, the adapter
 * class for the specific database will extend and instantiate it.
 *
 */

    class CI_DB_driver {

    var $username;
    var $password;
    var $hostname;
    var $database;

.......

    /**
     * Constructor.  Accepts one parameter containing the database
     * connection settings.
     *
     * @param array
     */
    function __construct($params)
    {
        if (is_array($params))
        {
            foreach ($params as $key =&gt; $val)
            {
                $this-&gt;$key = $val;
            }
        }
        $CI = &amp; get_instance();
        $this-&gt;database = $CI-&gt;session-&gt;userdata('database');

        log_message('debug', 'Database Driver Class Initialized');
    }....
</code></pre>

<p>Could you help me? </p>