What is MVC in Ruby on Rails?

by

Some background, MVC is a (compound) design pattern and was developed in 1979 by Trygve Reenskaug (Smalltalk).

True MVC was primarily planned for use in n-tier (non web) systems and it splits a system into 3 distinct parts, a Model, View and Controller

The Model

  • Contains data for the application (often linked to a database)
  • Contains state of the application (e.g. what orders a customer has)
  • Contains all business logic
  • Notifies the View of state changes (** not true of ROR, see below)
  • No knowledge of user interfaces, so it can be reused

The View

  • Generates the user interface which presents data to the user
  • Passive, i.e. doesn’t do any processing
  • Views work is done once the data is displayed to the user.
  • Many views can access the same model for different reasons

The Controller

  • Receive events from the outside world (usually through views)
  • Interact with the model
  • Displays the appropriate view to the user

** Classic MVC is not suited to web applications, as the model cannot send all changes to the view in an observer fashion (the view is a web page). The Model2 was introduced to overcome the changing infrastructure by JSP team in 90s . MVC Web frameworks are really not MVC, but Model2 (this is true of Ruby on Rails).

Here is a description of GUI patterns including MVC from the master, Martin Fowler
GUI Architectures

The best book I have found so far is Agile Web Development with Rails. It begins by assuming no knowledge, and is quite comprehensive.

Hope this helps to shed some light for you!

More Related Contents:

  1. Composite primary keys versus unique object ID field
  2. Can I get the name of the current controller in the view?
  3. Ruby on Rails Best practices – Big Controller vs Small Controller
  4. How to change the default path of view files in a Rails 3 controller?
  5. Rails Model, View, Controller, and Helper: what goes where?
  6. ActiveRecord.find(array_of_ids), preserving order
  7. file download link in rails
  8. Installing Postgres on windows for use with Ruby-on-Rails
  9. Devise + Omniauth – How to pass extra parameters along?
  10. Ruby on Rails Callback, what is difference between :before_save and :before_create?
  11. How to URL encode a string in Ruby
  12. Rails 4 – Gem::LoadError: Specified ‘mysql2’ for database adapter, but the gem is not loaded
  13. Rails: FATAL – Peer authentication failed for user (PG::Error)
  14. What is the difference between Gemfile and Gemfile.lock in Ruby on Rails
  15. How do I extract Rails view helpers into a gem?
  16. Passing variables inside rails internationalization yml file
  17. Parametrized get request in Ruby?
  18. How to make Devise redirect after confirmation
  19. Why is respond_with being removed from rails 4.2 into it’s own gem?
  20. sqlite3 gem fails to install
  21. Rails gem rails3-jquery-autocomplete: How do I query multiple fields
  22. API Authentication for user logged in to a Web App server
  23. database.yml &references not working
  24. How to create app-wide slug routing for Rails app?
  25. Rspec and capybara, difference between visit and get methods, with regards to the current_path object
  26. The better way to pass the foreign_key value to the Rails controller
  27. Rails4: How to permit a hash with dynamic keys in params?
  28. Why does adding “sleep 1” in an after hook cause this Rspec/Capybara test to pass?
  29. Heroku – Display hash of current commit in browser
  30. rails and backbone working together

Leave a Comment