add_topics.md

!SLIDE #let's add topics

• what exactly do we mean by "add topics?"
• rails "scaffolding" to generate some pages (and code)
• set up database with a new table (migration)
• review what we did

!SLIDE

adding topics

• topic will have a title and a description
• we will enable basic "CRUD" actions
  • Create - enter a new topic
  • Read - see everyone's topics
  • Update - change the topics you entered
  • Delete - remove your topics from the system

!SLIDE .

ruby script/generate scaffold topic title:string description:text
rake db:migrate

!SLIDE .

http://localhost:3000/topics

!SLIDE #What did we just do?

• a model
  • create app/models/topic.rb
  • create db/migrate/20090611073227_create_topics.rb
• 4 views
  • create app/views/topics/index.html.erb
  • create app/views/topics/show.html.erb
  • create app/views/topics/new.html.erb
  • create app/views/topics/edit.html.erb
• a controller
  • create app/controllers/topics_controller.rb
  • route map.resources :topics

!SLIDE

!SLIDE

Model-View-Controller

• Model
  • represents what is in the database
  • ActiveRecord
• View
  • the model rendered as HTML
  • ActionView, erb
• Controller
  • receives HTTP actions (GET, POST, PUT, DELETE)
  • decides what to do, typically rendering a view
  • ActionController

!SLIDE code .

git add .
git commit -m 'topic crud'
git push heroku master
heroku rake db:migrate