Problem in codeIgniter library does not return a value

I have the following library in codeIgniter that has functions getDbs() and getTables() in the

return $dbs; 

and

return tables;

the problem is they don’t return anything what am i doing wrong. Is it because i am using an array or sth

class Db_models {

    private $host;
    private $user;
    private $password;
    private $link;
    private $dbname;
    private $fields;
    public $dbs;

//TODO make this flexible especially connect statement
    public function __construct($config) {
        $this->host = $config[0];
        $this->user = $config[1];
        $this->password = $config[2];
        $this->link = mysql_connect($this->host, $this->user, $this->password);
        print_r($this->link);
    }

//Get Databases
    function getDbs() {

        $db_list = mysql_list_dbs($this->link);
        $row = mysql_fetch_object($db_list);
        var_dump($row);
        while ($row = mysql_fetch_object($db_list)) {
            $dbs[] = $row->Database;
        }

        return $dbs;
    }

//Get Tables
    function getTables($dbname) {
        $this->dbname = $dbname;
        $sql = "SHOW TABLES FROM $dbname";
        $result = mysql_query($sql);

        if (!$result) {
            echo "DB Error, could not list tables\n";
            echo 'MySQL Error: ' . mysql_error();
            exit;
        }

        while ($row = mysql_fetch_row($result)) {
            $tables[] = $row[0];
        }
        return $tables;
    }
//Get Fields
    function generateFields($dbname,$table){

        mysql_select_db($dbname, $this->link); 
        $result = mysql_query("SHOW COLUMNS FROM $table");
if (!$result) {
    echo 'Could not run query: ' . mysql_error();
    exit;
}
if (mysql_num_rows($result) > 0) {
    while ($row = mysql_fetch_assoc($result)) {
        $this->fields[]=$row;

    }
    return $this->fields;
}


    }


}

?> 

Here is my cotroller

<?php

if (!defined('BASEPATH'))
    exit('No direct script access allowed');

class Welcome extends CI_Controller {

    /**
     * Index Page for this controller.
     *
     * Maps to the following URL
     *         http://example.com/index.php/welcome
     *     - or -  
     *         http://example.com/index.php/welcome/index
     *     - or -
     * Since this controller is set as the default controller in 
     * config/routes.php, it's displayed at http://example.com/
     *
     * So any other public methods not prefixed with an underscore will
     * map to /index.php/welcome/<method_name>
     * @see http://codeigniter.com/user_guide/general/urls.html
     * 
     */
    private $fields=array('s'=>'s');

      public function __construct()
       {
            parent::__construct();
            $this->load->library('db_models', $config = array('localhost', 'madawar_Madawar', '23goodboys'));
       }
    public function index() {
       // $this->load->library('db_models', $config = array('localhost', 'Madawar', '23goodboys'));
        $data['dbs'] = $this->db_models->getDbs();
        $this->load->view('welcome_message', $data);
    }

    public function database() {
        $db_name = $this->input->post('database');
        $data['db_name'] = $db_name;
       // $this->load->library('db_models', $config = array('localhost', 'Madawar', '23goodboys'));
        $data['tables'] = $this->db_models->getTables($db_name);
        $this->load->view('database_dash', $data);
    }

    public function generate($dbname,$table) {


        /*$data = decode(TRUE);
        print_r($data);
        echo "sd";*/
       // $this->load->library('db_models', $config = array('localhost', 'Madawar', '23goodboys'));
       $data = $this->fields= $thi开发者_Python百科s->db_models->generateFields($dbname,$table);
       //print_r($data);
        $data=encode($data);
        echo $data;


    }

    public function getFields($some,$data) {

     echo $some;
     echo $data;
      // $this->load->library('db_models', $config = array('localhost', 'Madawar', '23goodboys'));
        $this->fields= $this->db_models->getFields();
    }


} 

They return arrays so use print_r to see what is returned.

Also if your using codeignier it has database support built in, your model should be using these functions not trying to re-implement them.