Question

Here is some code excerpted from Codeigniter’s user guide about models. There’s no explicit load of the databass class, in which the object db, method get in the code below have to be defined. I’ve checked the autoload file, there is no autoload of this specific class.

class Blogmodel extends CI_Model {

    var $title   = '';
    var $content = '';
    var $date    = '';

    function __construct()
    {
        // Call the Model constructor
        parent::__construct();
    }

    function get_last_ten_entries()
    {
        $query = $this->db->get('entries', 10);
        return $query->result();
    }

    function insert_entry()
    {
        $this->title   = $_POST['title']; // please read the below note
        $this->content = $_POST['content'];
        $this->date    = time();

        $this->db->insert('entries', $this);
    }

    function update_entry()
    {
        $this->title   = $_POST['title'];
        $this->content = $_POST['content'];
        $this->date    = time();

        $this->db->update('entries', $this, array('id' => $_POST['id']));
    }

}

Answer 1

The CodeIgniter documentation states two methods of loading the database library and connection:

Database – User Guide

Automatically Connecting

The “auto connect” feature will load
and instantiate the database class
with every page load. To enable “auto
connecting”, add the word database to
the library array, as indicated in the
following file:

application/config/autoload.php

Manually Connecting

If only some of your pages require
database connectivity you can manually
connect to your database by adding
this line of code in any function
where it is needed, or in your class
constructor to make the database
available globally in that class.

$this->load->database();

Also, when loading the model as referenced by jss:

You can tell the model loading
function to auto-connect by passing
TRUE (boolean) via the third
parameter, and connectivity settings,
as defined in your database config
file will be used:

$this->load->model(‘Model_name’, ”,
TRUE);