The MVC design pattern

One of the most popular application design patterns is Model-View-Controller (MVC). This defines three layers: the Model layer is in charge of data queries and persistence, such as loading and storing data to a database; the View layer is in charge of the User Interface (UI) and the Input/Output (I/O); and the Controller layer is in charge of business logic, which lies in between the View and the Model:

There are some frameworks that help developers to make MVC easier, such as Struts (https://struts.apache.org/), SpringMVC (https://projects.spring.io/spring-framework/), Ruby on Rails (http://rubyonrails.org/), and Django (https://www.djangoproject.com/). MVC is one of the most successful software design pattern, and is used for the foundation of modern web applications and services.

MVC defines a borderline between every layer, which allows several developers to jointly develop the same application. However, it also causes some negative side effects. The size of the source code within the application keeps getting bigger. This is because the database code (the Model), the presentation code (the View), and the business logic (the Controller) are all within the same VCS repository. This eventually has an impact on the software development cycle. This type of application is called a monolithic application. It contains a lot of code that builds a giant EXE or war program.