To Lecture Notes

IT 232 -- 10/21/15

1. What is a Rails action?
   Ans: It is a method in the controller. Usually this method is executed on behalf of a view, which is displayed after the action is executed. Sometimes an action is executed, and then redirected to a different action.
2. What is ActiveRecord?
   Ans: It is a ORM (Object Relational Mapping) that sits on top of SQL. ActiveRecord methods allow one to extract data from a database.
3. What are some ActiveRecord methods?
   Ans: all, first, last, where, order.
4. What is the difference between an array of model objects and an ActiveRecord relation?
   Ans: An ActiveRecord relation is a series of method calls that contain selected or transformed data from a database. Before this relation can be used, it must be changed into an array with the new, first, or last methods.
5. How do you know whether to use collection or member in config/routes.rb when adding a view to a scaffold-based project?
   Ans: Use member if the action applies to a specific id (row in the database). An example is the show view. Use collection when the action applies to all of the rows in the database, for example the index view.
6. Create a Rails scaffold-based project.
   
   1. Add models Doctor and Patient as in the Hospital Examples.
   2. Populate the doctors and patients tables with the seeds.rb file from the Hospital Examples.
   3. Add a page named directory that lists all of the doctors with their patients. Use nested unordered lists. Both the doctors should be displayed in alphabetical order. Also display unordered lists of the female and male patients separately, showing the doctor name for each patient.
   Ans: See the Hospital3 Example.

Designating a Root Page

• A root page is designated with a URL that does not include a controller or action specification.
• For localhost, the root page URL is
  

  http://localhost:3000
  

• To designate a root page, add this line to config/routes.rb:
  

  root 'doctors#index'
  

  or

  root 'welcome#home'
  

• To designate a root page with an id:
  

  root 'doctors#show', id: '1'
  

• The the Hospital3 Example has the doctors/directory page designated as the root node.

The Depot1 Example

• Implement the Depot1 project:
  

  Product:  cat_num  title  description  image_url  price
  Customer: first_name  last_name  address  cc_type  cc_num  cc_exp
  ShoppingCart: customer_id
  LineItem: product_id  shopping_cart_id
  

  Here are some images and a seed file for Product. See the Depot1 Example.
• Go to this URL to download example projects from the Ruby, Thomas, and Hansson textbook:
  
  http://pragprog.com/titles/rails4/source_code
• Look at the depot_* examples in the Rails 4.0.0 folder, where * = a to v.
• Run rake db:migrate and rake db:seed before starting the server and viewing the localhost webpages for the depot examples.
• We viewed the depot_c project today.
• If you are running Windows, run bundle update and update the coffee-script-source gem as usual.

FormHelper Methods

• Convert the TemperatureConverter2 Example to use FormHelper methods. See the TemperatureConverter3 Example for directions.

Simple Rails Authentication

• Here is a tutorial that shows how to add basic login authentication to a Rails project.
• Next week we will see how to write our own system that allows users to register and define their own passwords.