Programmatically: How to create custom Magento models

Step 1: Create a new PHP class

In the app/code/local directory, create a new directory for your module (e.g., MyCompany_MyModule). Inside this directory, create a new PHP file (e.g., Model.php) that will contain your custom model class:

		// app/code/local/MyCompany/MyModule/Model.php
namespace MyCompany\MyModule\Model;

class MyModel extends \Magento\Framework\Model\AbstractModel
{
    // Your custom model code here
}
	

Step 2: Define the model's properties and methods

In the MyModel class, you can define properties and methods as needed. For example, let's say you want to create a model that represents an order item:

		// app/code/local/MyCompany/MyModule/Model.php
namespace MyCompany\MyModule\Model;

class MyModel extends \Magento\Framework\Model\AbstractModel
{
    protected $_orderItemTable;

    public function __construct(
        \Magento\Framework\Model\Context $context,
        \Magento\Framework\Registry\Registry $registry,
        \MyCompany\MyModule\Model\ResourceModel\OrderItem $orderItemTable,
        array $data = []
    ) {
        parent::__construct($context, $registry, $data);
        $this->_orderItemTable = $orderItemTable;
    }

    public function getOrderId()
    {
        // Return the order ID associated with this model
    }

    public function getItemName()
    {
        // Return the item name associated with this model
    }
}
	

Step 3: Define the resource model

In Magento, the resource model is responsible for interacting with the database. You need to create a separate class that extends Magento\Framework\Model\ResourceModel\Db\AbstractDb. Let's create a resource model for our MyModel:

	// app/code/local/MyCompany/MyModule/Model/ResourceModel.php
namespace MyCompany\MyModule\Model\ResourceModel;

class MyResource extends \Magento\Framework\Model\ResourceModel\Db\AbstractDb
{
    protected function _construct()
    {
        $this->_init('my_table', 'entity_id');
    }

    public function load(\MyCompany\MyModule\Model\MyModel $model, $id)
    {
        // Load data from the database based on the given ID
    }

    public function save(\MyCompany\MyModule\Model\MyModel $model)
    {
        // Save data to the database
    }
}
	

Step 4: Register the model and resource model

In your module's etc/module.xml file, register the model and resource model:

	
	
	
    
        MyCompany\MyModule\Model
        MyCompany\MyModule\Model\ResourceModel
    
	
	

Step 5: Use the custom model

Now you can use your custom model in your module or elsewhere in your Magento application:

		// Example usage:
$model = \Magento\Framework\App\ObjectManager::getInstance()->get('MyCompany\MyModule\Model\MyModel');
$model->getOrderId(); // Get the order ID associated with this model
$model->getItemName(); // Get the item name associated with this model