The Model-View-Controller (MVC) architectural pattern is a way of structuring code in a way that separates concerns and makes it easier to maintain and extend. It is often used in web development to separate the presentation layer (the "view"), the data layer (the "model"), and the control flow (the "controller").
The Model represents the data and the business logic of the application. It is responsible for interacting with the database and performing any necessary calculations or transformations on the data. In Django, the models are defined as Python classes that inherit from the django.db.models.Model class.
The View is responsible for displaying the data to the user. In web development, views are usually implemented as functions or class-based views, that handle the HTTP request and return the HTTP response. In Django, views are defined as functions or classes that handle a specific URL and return an HTTP response. The views can use the data provided by the models to generate the HTML, XML or JSON response.
The Controller is responsible for coordinating the actions of the model and the view. In web development, the controller is often implemented as a routing mechanism that maps URLs to specific views. In Django, the controller is implemented as the "URL dispatcher" that maps URLs to views based on the URL patterns defined in the urls.py file.
The main advantage of using the MVC pattern is that it promotes the separation of concerns. The models and views are decoupled and can be reused in different parts of the application. This allows for a more modular and testable codebase, that is easier to maintain and extend.
MVC is not limited to web development, it's a general pattern that can be applied in other kinds of software. For example, in a desktop application, the model could represent the data, the view could be the graphical user interface, and the controller could handle the events and interactions between the two.
It's worth mentioning that there are different variations of MVC, such as the Model-View-View-Model (MVVM) and the Model-View-Presenter (MVP), that slightly change the responsibilities of the components.