MVC Framework In A Nutshell

The MVC framework is a predictable software design pattern separated into three main components and suitable for many programming languages. The goal of the MVC framework is to help structure the code-base and separate application concerns into three components: View, Model, and Controller.

Aspect	Description
Definition	The Model-View-Controller (MVC) Framework is a software architectural pattern used for designing and organizing applications. It separates an application into three interconnected components: Model, View, and Controller, to promote modularity, maintainability, and scalability.
Process	1. User Interaction: User interacts with the View, initiating an action. 2. Controller Handling: Controller receives the user’s input, processes it, and decides how to proceed. 3. Model Update: Controller updates the Model based on user input or application logic. 4. View Update: Model changes are reflected in the View for the user to see.
Metrics	Metrics for evaluating MVC effectiveness include code modularity, reusability, testability, and maintainability. Performance metrics may be specific to the application domain.
Benefits	– Separation of Concerns: Clear separation between data (Model), presentation (View), and control logic (Controller). – Modularity: Each component can be developed, tested, and maintained independently. – Code Reusability: Components can be reused in different parts of the application. – Maintainability: Easier to maintain and extend over time.
Drawbacks	– Complexity: MVC can introduce complexity, especially in small applications. – Learning Curve: Developers need to understand the pattern well. – Overhead: Extra layers may lead to overhead in simple applications.
Applications	– Web Development: MVC is widely used in web frameworks like Ruby on Rails, Django, and ASP.NET. – Desktop Applications: Used in desktop GUI applications for maintaining code structure. – Mobile App Development: MVC variants are applied in mobile app development. – Game Development: Some game engines use MVC or similar patterns.
Use Cases	– E-commerce Website: Separates product data (Model), product listings (View), and shopping cart logic (Controller). – Task Management App: Divides task data (Model), task display (View), and task manipulation (Controller). – Mobile Chat App: Separates user data (Model), chat interface (View), and message handling (Controller).
Examples	– Web Application: In a web app, the Model stores user data and business logic, the View displays web pages, and the Controller handles user requests. – E-commerce Platform: Product data (Model), product listings (View), and shopping cart functionality (Controller). – To-Do List App: Task data (Model), task display (View), and task creation/editing (Controller).

Table of Contents

Understanding the MVC framework

The MVC framework was developed in response to the changing nature of web development.

Traditionally, projects simply involved uploading static CSS, HTML, and JavaScript files to a HTTP server.

But with the growing popularity of software-as-a-service (SaaS), applications once destined for the desktop are being incorporated into browsers.

In many cases, these applications are large and complex. JavaScript alone cannot be relied upon to provide a stable foundation for quality code.

The MVC framework encourages developers to write more structured JavaScript code through design patterns.

From humble beginnings in desktop graphical user interfaces, the framework has become popular in web and mobile app development.

The MVC framework can support high user interaction and real-time server communication with maintainable and testable code.

The three components of the MVC framework

Component	Description
Model	– Represents the application’s data and business logic. – Responsible for data retrieval, storage, and manipulation. – Independent of the user interface (UI) and presentation logic.
View	– Presents the data to the user and handles the user interface (UI). – Receives input from the user and sends it to the Controller. – Typically displays data from the Model.
Controller	– Acts as an intermediary between the Model and the View. – Processes user input, invokes actions in the Model, and updates the View. – Orchestrates the application’s logic and flow.

The goal of the MVC framework is to help structure the code-base and separate application concerns into three components:

View

Or the presentation of data collected from model data in the form of charts, tables, or diagrams.

This includes any customer view of the user interface and its components such as drop-down menus or text boxes.

Model

Or data used by a program.

This is often in the form of a database but can also represent an object, icon, or video game character.

Controller

The part of the application handling user interaction in the form of mouse and keyboard inputs.

The controller accepts inputs from views and models to provide a corresponding update.

A controller can update the model of a video game character by changing an attribute such as endurance.

The view is then updated to reflect the change in the endurance attribute during gameplay.

When should the MVC framework be used?

As stated, the MVC framework should be used for any application where JavaScript will struggle to do the heavy lifting on the client-side.

If a business wants to build an application with a focus on the server-side, then the MVC framework is probably unsuitable.

Nevertheless, certain criteria can help developers determine whether the framework is suited to their project.

These criteria encompass applications that:

Require an asynchronous connection to the backend.
Shouldn’t require full page reload functionality, such as adding post comments or infinite scrolling.
Render the same data in different ways.
Contain numerous trivial interactions that modify data, such as switches or buttons.
View or manipulate data within the browser itself, and not on the server.

As a reference point, consider that many popular web applications such as Google Docs, Gmail, and Spotify fulfill all the above criteria.

MVC framework examples

Here is an example of how the MVC framework is implemented in a real-world application using PHP.

The app in question is a currency converter that will convert a chosen currency – in this case euros – into several others and show their respective values.

With that in mind, let’s discuss each of the three components below.

The model

To start, it is important to solve the base problem of performing the currency conversion. The simple class “CurrencyConverter” is created which stores different exchange rates relative to EUR for the AUD, GBP, and USD.

The class also stores a specific amount of the currency which in this case is 100 EUR. This base value is not accessible directly, but can nevertheless be used to convert 100 EUR into the equivalent amount of the other three currencies.

If an app user wanted to convert 100 AUD into EUR, GBP, or USD, for example, another class could be created. Note that the converter functions without knowledge of how it will be used or the architecture in which it will be incorporated.

The view

Since the user will enter an amount of currency they wish to convert, the app will require an input box and submit button to perform the calculation.

The developer also believes it is worth displaying the particular currency being converted, so the view will need to understand the currency it is working with. The developer then writes the code for an input box with a “Convert” button the right-hand side and the currency to be converted on the left-hand side.

At this point, the input box does not yet know about the converter and is thus not displaying anything meaningful. To have the view display the values contained in the model, the developer writes additional code and tests the model by entering a value and seeing whether it will perform the conversion.

Usability

The input box with a sole currency and “Convert” button is not terribly useful – particularly if the user wants to see the exchange rate for multiple currencies. Since usability is a core tenet of the MVC framework, the view can be reused multiple times to show additional currencies.

Now, the developer has four input boxes and four buttons. Each box is labeled with AUD, GBP, USD, and EUR.

The controller

To enable the user to make a currency conversion calculation, the developer turns their attention to the “Convert” button. In this case, the controller must take what value the user enters and update the model to reflect it.

The developer writes code that uses the form field names they previously created in the view. The controller is made testable and reusable with an array that is passed in as an argument. In other words, the controller is instantiated once and used by all four views.

To conclude, the developer writes code to initialize the app. This enables the user to perform a currency conversion by entering a value for either of the four currencies and clicking “Convert”.

Case Studies

E-commerce Platform: An e-commerce website can use the MVC framework to separate the presentation layer (View) from the business logic (Controller) and the database (Model). This allows for easy updates to the user interface without affecting core functionality.
Customer Relationship Management (CRM) System: CRM systems benefit from MVC as they deal with a large volume of data and user interactions. The Model manages customer data, the Controller handles user interactions, and the View displays customer information and interaction history.
Inventory Management System: In a business that manages inventory, the MVC framework can be used to keep track of products (Model), manage inventory levels and orders (Controller), and display product availability and order status to employees (View).
Financial Analysis Software: Financial software can utilize the MVC pattern to separate data storage and processing (Model), user input and calculations (Controller), and financial reports and dashboards (View).
Online Banking Application: MVC can be employed to build secure online banking applications. The Model deals with account data, the Controller handles user transactions and security, and the View presents account balances and transaction history.
Human Resources Management System (HRMS): An HRMS can utilize MVC to manage employee data (Model), process leave requests and payroll (Controller), and provide employees with access to their information, benefits, and performance evaluations (View).
Project Management Software: Project management tools can use the MVC framework to store project data (Model), allow users to create tasks and timelines (Controller), and provide Gantt charts and progress reports (View).
Hotel Reservation System: In the hospitality industry, MVC can help manage room availability and pricing (Model), handle customer reservations and check-ins (Controller), and display room options and rates to customers (View).
Online Learning Platform: Learning platforms can use MVC to store course content and student data (Model), manage course enrollments and assignments (Controller), and provide students with an interactive interface for accessing course materials (View).
Supply Chain Management: In supply chain management, the MVC framework can help track inventory levels (Model), manage orders and shipments (Controller), and offer real-time visibility into supply chain processes (View).
Social Media Platform: Social media applications benefit from MVC to store user profiles and content (Model), handle user interactions and content sharing (Controller), and display personalized feeds and user profiles (View).
Travel Booking Portal: Travel websites can use MVC to manage flight and hotel information (Model), handle booking and payment processing (Controller), and present travel options and booking details to users (View).
Healthcare Information System: Healthcare systems can utilize MVC to store patient records and medical data (Model), manage appointments and billing (Controller), and provide healthcare professionals with access to patient information (View).
Online Retail Analytics Dashboard: In the retail industry, MVC can be employed to collect and analyze sales data (Model), allow users to customize reports and queries (Controller), and display sales trends and performance metrics (View).
Legal Case Management Software: Legal firms can use the MVC framework to store case information and documents (Model), manage case activities and deadlines (Controller), and provide lawyers and clients with access to case details and updates (View).

Key takeaways

The MVC framework is a software design pattern incorporating three core components: view, model, and controller. Each component handles a specific development aspect of an application.
The MVC framework is used in large and complex applications where JavaScript on the client-side cannot provide a foundation for stable, quality code.
To determine whether the MVC framework is suitable for their build, businesses can consult a list of criteria common to popular web applications such as Google Docs and Spotify.

Key Highlights

MVC Framework Overview:
- The MVC framework is a software design pattern used to structure code in various programming languages.
- It separates application concerns into three main components: View, Model, and Controller.
- The goal is to enhance code organization, maintenance, and separation of concerns.
Purpose and Origin:
- The MVC framework was developed in response to the evolving nature of web development.
- It arose from the need to manage complex applications and facilitate structured JavaScript code.
- Originally used in desktop graphical user interfaces, it became popular in web and mobile app development.
Components of MVC:
- View: Represents the presentation of data derived from the model. It includes user interface elements like charts, tables, and diagrams.
- Model: Holds the application’s data. This can be a database or represent objects, icons, characters, etc.
- Controller: Handles user interactions, such as mouse and keyboard inputs. It updates the model and communicates with the view accordingly.
Suitability and Criteria:
- MVC is recommended for applications where JavaScript struggles to handle complex client-side tasks.
- It’s not suitable for applications focused on server-side processing.
- Criteria for MVC use include asynchronous backend connections, partial page reloads, rendering data differently, trivial data interactions, and client-side data manipulation.
Examples of MVC Framework:
- An example currency converter application is used to illustrate the implementation of MVC.
- Model: “CurrencyConverter” class holds exchange rates and currency amounts for conversion.
- View: User interface elements such as input boxes and buttons for currency conversion.
- Controller: Handles user input, updates the model, and interacts with the view for display.
Key Takeaways:
- The MVC framework organizes applications into view, model, and controller components.
- It’s particularly beneficial for managing complex applications where JavaScript alone might not suffice.
- Criteria like asynchronous connections, partial page reloads, and client-side data manipulation help determine if MVC is suitable for a project.