The model is responsible for handling the data of your application. Models receive input from Controllers and manage the application’s data, including inserting, updating, and retrieving information from the database.

Key Responsibilities of a Model:

• Managing Data: Models interact with the database by performing CRUD (Create, Read, Update, Delete) operations.
• Interaction with Controllers: Models receive input from Controllers and process the data accordingly.

Location of Models:

Model classes are located in the application/models/ directory and can be organized into sub-directories.

Creating a Basic Model in CodeIgniter 3

Basic Syntax for Creating a Model

The basic structure of a Model in CodeIgniter 3 is as follows:

class Model_name extends CI_Model {

}

Rules:

• The filename must match the class name and should start with an uppercase letter.
• The class should extend the CI_Model class.

Example: Creating a Blog Model

Let’s walk through a practical example to understand how a Model works in CodeIgniter 3.

class Blog_model extends CI_Model {

	public function add() {
		$data = [
			‘title’		=> ‘Title’,
			‘description’	=> ‘Description’
		];
		// insert(‘table_name‘, ‘array_of_object’)
		$this->db->insert(‘blog_info’, $data);
	}

	public function get_blog_list() {
		$query = $this->db->get(‘blo_info’);
		return $query->result();
	}
}

Explanation:

1. Defining the Model: Blog_model is defined with methods add() and get_blog_list().
2. Inserting Data: The add() method inserts a new record into the blog_info table.
3. Fetching Data: The get_blog_list() method retrieves all records from the blog_info table.

Loading a Model in CodeIgniter 3

To use a Model in your Controller, you need to load it first. The load->model() method is used to load a Model in CodeIgniter 3.

Basic Syntax:

Load a Model

A this->load->model() method is used to load a model.

The basic syntax is as follows:

$this->load->model('model_name');

Loading a Model from a Sub-directory

If your Model is inside a sub-directory, you need to specify the relative path from the models directory.

For example, if your Model is located at application/models/user/Profile.php, you would load it as follows:

$this->load->model('user/profile');

Accessing Model Methods

Once the Model is loaded, you can access its public methods using an object with the same name as the Model class:

$this->load->model('model_name');
$this->model_name->method();

Example: Loading and Using a Model in a Controller

Here’s an example of a Controller that loads the Blog_model and uses its methods:

class Blog extends CI_Controller {

	public function index() {
    	$this->load->model(‘blog_model’);

        $data[‘list’] = $this->blog_model->get_blog_list();

        $this->load->view('about_us', $data);
   	}
}

Explanation:

1. Loading the Model: Blog_model is loaded using $this->load->model('blog_model');.
2. Using Model Methods: The get_blog_list() method is called to fetch the list of blogs.
3. Passing Data to the View: The fetched data is passed to the about_us view.