What is MVC in Ruby on Rails?

Question

Could someone please explain MVC to me in Ruby on Rails, in layman terms. I am especially interested in understanding the Model in MVC (can\'t get my head around the model).

Answer 1

Ruby on Rails does not implement the MVC design pattern. Ruby on Rails has folders called controllers, models, and views. The views folder has HTML files. The controllers and models folder have ruby files. The controllers map to a URL and a method in the controller gets executed upon requesting that URL, the associated view (HTML file) gets loaded and the model (data structure) for it is used to populate the view. Thats the extent of it's likeness to the MVC design pattern. It's a shame that people say it's MVC because it's caused a generation of confusion and misunderstanding of the MVC design pattern.

In Rails, the model is a data structure.

Answer 2

The Model View Controller principle divides the work of an application into 3 separate but closely cooperative subsystems.

Model (ActiveRecord ):

It maintains the relationship between the objects and the database and handles validation, association, transactions, and more.

This subsystem is implemented in ActiveRecord library, which provides an interface and binding between the tables in a relational database and the Ruby program code that manipulates database records. Ruby method names are automatically generated from the field names of database tables.

View ( ActionView ):

It is a presentation of data in a particular format, triggered by a controller's decision to present the data. They are script-based template systems like JSP, ASP, PHP, and very easy to integrate with AJAX technology.

This subsystem is implemented in ActionView library, which is an Embedded Ruby (ERb) based system for defining presentation templates for data presentation. Every Web connection to a Rails application results in the displaying of a view.

Controller ( ActionController ):

The facility within the application that directs traffic, on the one hand, querying the models for specific data, and on the other hand, organizing that data (searching, sorting, messaging it) into a form that fits the needs of a given view.

This subsystem is implemented in ActionController, which is a data broker sitting between ActiveRecord (the database interface) and ActionView (the presentation engine).

Check the links below for clear understanding of mvc in rails:

http://www.bogotobogo.com/RubyOnRails/RubyOnRails_Model_View_Controller_MVC.php

https://betterexplained.com/articles/intermediate-rails-understanding-models-views-and-controllers/