Brief introduction to basics of Ruby on Rails.

1. Ruby on RailsJune 17, 2011Elpizo Choi

2. What is Ruby on Rails? MVC Framework for building web apps in Ruby Uses Ruby classes to abstract out the various components of an app Convention over configuration

3. Main Components ActiveRecord(ORM – think hibernate) ActionController(business logic, routing) ActionView(template parser) Migrations, rake tasks

4. Creating a Rails app

5. Basic folder structure apps folder controllers, models, views – where you’ll spend most your time database.yml Configures database Gemfile Configures external libraries used in app

6. … a little configuration

7. …a little configuration

8. Let’s make a model

9. ActiveRecord::Base When inherited, maps to table that’s plural of class name Team -> teams Basic methods Team.create() Team.find() Team.where().limit().sort().skip().first Team.where().limit().sort().skip().all

10. …first we need to create table

11. …first we need to create table

13. rake –T to see all available tasks

14. rake db:migrate will run all database migrations that haven’t been run

16. Querying More in-depth tutorial: http://guides.rubyonrails.org/active_record_querying.html

17. The “web” part of web-app

18. Let’s get this running

19. What happened?

20. What happened?

21. What happened? config/routes.rb defines how urls are mapped to controllers get “teams/index” is shorthand for: match “teams/index” => “teams#index”, :via => :get More details: http://guides.rubyonrails.org/routing.html Read comments in config/routes.rb

22. Let’s make some changes

23. Let’s make some changes

24. Let’s make some changes

26. All code in the corresponding method will happen as side effects

29. <% %> tag: Ruby code to be run, but not shown

30. <%= %>tag: Ruby code to be run and shown

32. Creating relationships Create the player Add foreign key

33. Creating relationships

34. Creating relationships Gotta reload console after changing models Get players

36. for records whose foreign key column corresponds to the current class (team_id)

38. We can now change our view

39. We can now change our view

40. More associations ActiveRecord also has shortcuts for: has_and_belongs_to (join tables) Polymorphic associations (belongs_to different objects) http://guides.rubyonrails.org/association_basics.html

41. Congratulations! You’ve made your first Rails app

42. Additional Resources Source code for example_app: https://github.com/fuJiin/example_app See it live: http://cg-example-app.heroku.com/teams/index Documentation and light tutorials: http://guides.rubyonrails.org/ More in depth: http://ruby.railstutorial.org/ruby-on-rails-tutorial-book

43. Questions?