Architectural patterns for beginners: MVC, MVP, and MVVM

 Introduction to Architectural Design

When discussing architectural patterns in software design, the first ones that come to mind include client-server architecture, layered architecture, monolithic architecture, microkernel architecture, and event-driven architecture. These patterns relate to the overall system architecture, encompassing multiple applications, services, servers, and so on.

However, MVP, MVC, and MVVM focus on organizing code within an application by separating data, user interface, and logic. These are subsets of architectural patterns that focus on the overall system.

TERMS:

• Model-View-Controller (MVC)

• Model-View-Presenter (MVP)

• Model-View-ViewModel (MVVM)

1. Model-View-Controller (MVC)

Model

This includes all the code related to the data contained within the software. It's the layer that handles communication between the database and the network layer with the rest of the application. Its main responsibilities include:

• Data processing and business logic

• Encapsulate application data and rules for managing access to that data.

• Data structure management

• Perform CRUD (Create, Read, Update, and Delete) operations on the data.

View

It's the user interface of your application—everything the user can see and interact with. It's also known as your application's User Interface (UI). Its responsibilities include:

• Handling non-business logic and purely presentation logic.

• Presenting data provided by other classes to the user.

• Receive user input and forward it to other layers.

• It may or may not be possible to communicate directly with the Model layer.

Model-View-Controller (MVC) Architecture

With an understanding of Model and View classes, explore individual architectural patterns.

Controller

MVC uses one Controller. This layer communicates with both the Model and View layers. The Controller's main responsibilities include:

• Data manipulation through the Model layer

• Get instructions from the View (User Interface) class.

• Update the View with the changes defined by the control logic.

In MVC, the View layer cannot directly interact with the Model layer; it can only receive updates based on changes in the data. Therefore, all three layers are interconnected, with the Controller being the central component.

2. Model-View-Presenter (MVP)

Model-View-Presenter (MVP) Architecture

IN MVP, the Presenter acts as an "intermediary" between the Model and View classes, handling all communication between them. There is no direct communication between the Model and View classes.

The presenter's responsibilities include:

• Update the UI or View class based on user actions.

• Update the Model class based on business logic.

• Handles most of the business logic that the Controller handles in MVC.

3. Model-View-ViewModel (MVVM)

Model-View-View Model (MVVM) architecture

At first glance, they may look similar to MVP, but there are key differences:

• Multiple views can be mapped to a single ViewModel class.

• Using data binding between the ViewModel and View classes makes it more event-driven.

• The View class represents user actions, not the interface itself.

Parallel comparison

Face	MVC	MVP	MVVM
Full name	Model-View-Controller	Model-View-Presenter	Model-View-ViewModel
Separate concerns	Foundation	Better	Best
Data flow	two-way	One way	One-way with data constraints
Logical-view relationship	Many-one	One-on-one	Many-one
Testability	Hard	Good	Best
MAINTENANCE	Hard	Easy	Easy
Learning curve	Easy	Easy	More difficult
Efficiency	It may be slower due to tight joints.	Better performance with a looser coupling.	Smooth performance, especially for complex user interfaces.
User interface update	Update View controller	Presenter updates: View	ViewModel updates View via data binding
Dependence on UI Frameworks	High	Short	Little or no dependence
Scalability	Suitable for small-scale projects.	Suitable for both simple and complex projects.	Ideal for large, data-intensive applications.

Popularity and application

All three architectures are equally popular and are used based on a company's specific requirements for a product.

Many companies use a combination of these architectures depending on the specific needs of each project or product. The choice of architecture often depends on factors such as the complexity of the application, the expertise of the development team, and the specific requirements of the project.

Conclusion

This article covers the fundamental concepts of architectural patterns, from how to design the overall architecture to how a single application can be divided into three components for better management and scalability.

• MVC: With its simple approach, it remains popular for web applications.

• MVP: Built on the MVC framework, it offers improved testability and a clearer separation of concerns.

• MVVM: The most recent of the three has gained considerable traction in the development of modern applications.

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