Model within a model

Is it possible to include a model in the '__construct' and do the same with the other model?

PHP Code:

class Users_model extends \App\Models\BaseModel {

    function __construct()
    {
        // Call the Model constructor
        parent::__construct();
 $this->Settings = model('Settings_model');
    }
} 


PHP Code:

class Settings_model extends \App\Models\BaseModel {

    function __construct()
    {
        // Call the Model constructor
        parent::__construct();
 $this->Users = model('Users_model');
    }
} 


When I do this, I always get a 503 Service Temporarily Unavailable error. Is there a workaround for this?

Untested, but this should work:

PHP Code:

<?php

namespace App\Models;

use CodeIgniter\Model;
use App\Models\UserModel;


class LoggingModel extends Model
{

    public function __construct()
    {
        parent::__construct();
        $this->user = new UserModel();
    }
} 


Thanks for your response. But can I call the LoggingModel in the UserModel the same way?

I can't think of any reason why not, have you tried? 

To match your model names:

PHP Code:

<?php

namespace App\Models;

use CodeIgniter\Model;
use App\Models\Settings_model;
class Users_model extends Model {

    function __construct()
    {
        // Call the Model constructor
        parent::__construct();
        $this->Settings = new Settings_model();
    }
} 


PHP Code:

<?php

namespace App\Models;

use CodeIgniter\Model;
use App\Models\Users_model;
class Settings_model extends Model {

    function __construct()
    {
        // Call the Model constructor
        parent::__construct();
         $this->Users = new Users_model();
    }
} 


If each model is a dependency of the other and called in each constructor, there exists a cyclic dependency, or circular reference. You cannot do that. It will result to infinite recursion of Users model calling Settings model calling Users model calling Settings model and so forth.

From your current situation, your models are tightly coupled to each other. You should rethink ways to decouple your code.

HINT: Like using a BaseModel and then extending all your models from the BaseModel.

What did you Try? What did you Get? What did you Expect?

Joined CodeIgniter Community 2009.  ( Skype: insitfx )

Thanks for your responses. What InsiteFX suggested was my first idea but I had the same problem with that. I'm using it like this (just like the Settings_model):

PHP Code:

namespace App\Models;
use CodeIgniter\Model;
class Users_model extends \App\Models\BaseModel {

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


And my BaseModel looks like this:

PHP Code:

namespace App\Models;
use CodeIgniter\Model;
class BaseModel extends Model {

    public function __construct(){
        $this->session = \Config\Services::session();
        
        $this->Settings = model('Settings_model');
        $this->Users = model('Users_model');
    }
} 


So both have the Settings_model and the Users_model because they get it from the BaseModel. I thing this is getting the same error because it is the same idea of what paulbalandan is saying. Or maybe it is because I'm trying to fix my CI3 project in CI4, so it might has something to do that those models aren't correctly converted yet.

Are the examples above best practice or do I mis something?

By any chance, why do you need an instance of Users model inside Settings model, and vice versa?

Hi, In general, I call models from controllers. However, here is an example where I've called Customers model from Orders model. Hope this helps.

Models/BaseModel.php

PHP Code:

<?php

namespace App\Models;

use CodeIgniter\Model;

class BaseModel extends Model
{
  protected $db;

  protected function __construct()
  {
    $this->db = \Config\Database::connect();
  } 


Models/Customers.php

PHP Code:

<?php

namespace App\Models;

use App\Models\BaseModel;

class Customers extends BaseModel
{
  protected $fields;

  public function __construct()
  {
    parent::__construct();
  }

  public function getCustomer(int $customerId)
  {
    $builder = $this->db->table('customers c');
    $query = $builder->select($this->fields['customers-all'])->where('c.id', $customerId)->get();
    return $query->getRowArray();
  } 


Models/Orders.php

PHP Code:

<?php

namespace App\Models;

use App\Models\BaseModel;

class Orders extends BaseModel
{
  protected $orderTable;
  protected $selectFields;

  public function __construct()
  {
    parent::__construct();
  }

  public function getOrder(int $orderId)
  {
    $c = new \App\Models\Customers;

    $query = $this->orderTable->select($this->selectFields['all'])->where('o.id', $orderId)->get();

    $order = $query->getRowArray();
    if (!$order) {
      return ['order' => $order];
    }

    $orderItems = $this->getOrderItems($orderId);
    $customer = $c->getCustomer($order['customer_id']);
    $address = $c->getAddress($order['address_id']); 


By any chance, why do you need an instance of Users model inside Settings model, and vice versa?

Because in some functions of the Settings_model I need data from the users and in the Users_model I need data from the settings. That might not be best practice, but that's the situation.