Have you often heard the term "MVC model" in system development?
It is an important design model for development because it separates program processing by function to make it easier to organize the program, but many people may not fully understand it.
This time, we will explain the background and benefits of the MVC model in an easy-to-understand manner, starting with its outline and role. This is a must-read for those considering development or those studying system development. Please watch till the end.
Through my personal exploration in the realm of system development, I've consistently encountered a fundamental concept: the MVC model. Standing for Model, View, and Controller, MVC is more than an acronym; it's a cornerstone in system design models. When I first asked, "What is MVC?" I realized its significance in structuring applications for better maintainability and operational efficiency.
But MVC isn't just a theoretical model; it's a practical framework. Delving into "What is MVC framework?" led me to appreciate how it elegantly separates an application's logic, interface, and control flow. This separation not only simplifies development but also enhances project management, a critical aspect in our company's approach to app development and digital transformation.
One key element of this model that piqued my interest is the Controller. Understanding "What is a Controller in MVC?" was a turning point. It acts as an intermediary between the Model, which represents the data and the business logic, and the View, which is the user interface. This division ensures a clean separation of concerns, an aspect I've found invaluable in streamlining our development processes.
Furthermore, "What is MVC structure?" encompasses this triad of components working in harmony. It's a structure that promotes organized coding and efficient team collaboration, which is essential in our dynamic environment of constant innovation.
Lastly, exploring "What is the MVC framework?" in the context of various programming languages and platforms helped me comprehend its versatility and adaptability in different tech environments. This understanding has been instrumental in guiding our strategies for system and app development, ensuring we stay at the forefront of technological advancements.
The MVC model has a long history and was devised by Trygwerenskaug at the Palo Alto Research Institute in 1979.
Initially, Smalltalk was a programming language and comprehensive development environment intended for use in designing window programs (applications that run in multiple windows on a computer's desktop). In software development at the time, they realized the complexity of software development and the need to separate and manage responsibilities, and proposed an architecture that made each role independent . This is the beginning of the MVC model.
Later, the specifications for software GUIs (Graphical User Interfaces: graphical interfaces for interaction between users and computers) became more complex, and the MVC model became more useful and versatile in the development of software and web systems with GUIs. It has started to attract attention. In particular, the adoption of the MVC model by JavaServer Pages (JSP) was a major impetus, and the MVC model became widely used.
What are the M, V and C in MVC Model?
・Model
The Model is responsible for communicating with the database, performing appropriate operations and processing such as registering, updating, and deleting data, and providing processing results to the Controller. When the Controller receives a request from the client and instructs the Model to retrieve, save, update, or delete data, the Model retrieves information from the database, processes the data as necessary, and returns it to the Controller.
・View
View has the role of receiving data, displaying it with a creative design and layout, and providing it to the user as an easy-to-use and operable screen (= computer or smartphone screen). The Controller processes the data received from the Model and sends it to the View. However, since it cannot be displayed on a web browser as it is, View plays the role of displaying the screen using HTML, CSS, JavaScript, etc.
・Controller
The Controller plays an intermediary role, receiving user input (requests) from the View, instructing the Model to perform appropriate processing, and transmitting the results to the View. The controller detects information received from the Model, instructs the Model to retrieve data or perform other operations, and sends that data to the View to update it and display the new information.
There is a design derived from the MVC model called MVVM (Model-View-ViewModel). This means that in addition to the Model and View, the ViewModel takes on some of the functions of the Controller.
In modern application development, due to factors such as the advent of data binding (a mechanism that automatically associates data with UI elements), improved maintainability, and a shift to component orientation, user actions and data changes are reflected directly in views. It is now possible to do so . As a result, the functionality of traditional Controllers has faded, and in their place ViewModels have emerged to mediate data and commands between Views and Models and manage View logic.
The differences between MVC and MVVM are as follows.
・Impact of any changes or modifications
MVC is easy to change and modify because each function is independent, but MVVM is more complicated to change and modify than MVC.
・Data synchronization
MVC requires the intermediary of a Controller in order to reflect it in the View, which increases the number of interactions between components, which can slow down operation. On the other hand, MVVM has the feature of data binding, where if a value is changed in either the View or the View Model, both values are changed, so updating the UI is easy and fast.
・Easy to proceed with work
MVC allows you to work efficiently because each function is separated, but MVVM has the View and Model together, which makes it difficult to separate labor and can slow down work.
・Ease of testing and maintainability
In MVC, the Controller acts as an intermediary between the Model and View, but this reduces structure and maintainability. On the other hand, in MVMM, the ViewModel takes on that role, which separates the business logic and UI, making the code organized and easier to test and maintain.
The MVC model is centered around requests from users, and controllers receive requests and begin processing them. Below is the flow.
The request is received from the user and processed by the Controller.
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The Controller responds to requests and instructs the Model on what data to process.
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Model returns the data processing results to the Controller
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The Controller processes the data sent from the Model and sends it to the View.
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View is displayed on screen and can be seen by the user
Because each role in MVC is completely independent, the code is clear, easy to manage, and easy to reuse and maintain . If roles are not divided in this way, the amount of code will be enormous, and it will be difficult to understand which code plays which role, which will be inconvenient both during and after development.
Up to this point, I think you have understood the roles of Model, View, and Controller, but I think there are many people who think they understand the flow part but don't understand. . Here, we will compare the MVC model to an "airline ticket reservation site".
View
The user accesses the flight ticket search screen, enters information such as "departure point, destination, date" and clicks the search button.
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Controller
The entered information is sent to the Controller. The Controller accesses the Model and retrieves information from the database based on the entered ticket conditions. At this time, messages such as "Searching'' and "Loading'' are displayed on the user's screen.
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Model
Returns information on airline tickets that meet the conditions to the Controller.
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Controller
Pass the flight ticket information obtained from the Model to the View.
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View
The user selects the desired ticket from the displayed airline tickets. That information is sent to the Controller again.
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Controller
Access the Model and reserve the selected ticket.
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Model
Save information about reserved tickets in the data veil.
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View
A message will be displayed to the user confirming that the reservation has been completed.
The MVC model also has good compatibility and bad compatibility depending on the scale and content of development. Let's understand the advantages and disadvantages so that you can make a decision.
・Efficient
In MVC, the codes for three highly specialized functions are independent, so when making modifications or additions, it is easy to understand which code is related to which, making it easy to manage the code. This makes it easier to divide work and do it more efficiently.
・Excellent maintainability
In MVC, each function is divided and developed independently, so unnecessary information is not mixed, and when changing a specific function, it is less likely to affect unrelated parts. Therefore, for example, even if a bug occurs in the View, it will not affect the Model or Controller, allowing you to identify the cause and fix it quickly.
・Code can be reused
Code can be reused within each component. For large projects, code reuse can reduce development time and improve code quality.
・Unsuitable for some projects
When developing small applications, MVC models can be over-engineered, increasing development time and costs.
・Performance impact
The MVC model has split code and three components interacting with each other, which can slow things down. Performance may be affected in real-time applications.
Up to this point, we have explained the background of its birth, detailed overview, and advantages and disadvantages of MVC, which is one of the important design models in system development.
I hope you will remember the "MVC model", which allows for efficient development and can be used for corporate structures and mechanisms.
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