In CodeIgniter, how can you use Models to implement data validation rules?

In CodeIgniter, Models can be utilized to implement data validation rules by incorporating validation logic within Model methods. The $this->form_validation library is typically used in Controllers for form validation, but within Models, developers have the flexibility to define custom validation rules and logic tailored to the data layer. This approach helps maintain separation of concerns and ensures that data validation is an integral part of the overall application architecture.