To Lecture Notes

IT 231 -- 9/28/15

Review Questions

1. Create a Rails scaffold project. In the upper right corner of each view, show the date and time like this (look right):

9/28/15   1:38 PM

At the bottom of the controller, define this private method


def get_time
  t = Time.now
  h = t.hour
  min = t.min
  s = t.sec
  m = t.mon
  d = t.day
  y = t.year
  if h == 0
    h = 12
    am_pm = "AM"
  elsif h < 12
    am_pm = "AM"
  elsif h == 12
    am_pm = "PM"
  elsif h > 12
    h = h - 12
  end
  @time_string = "%d/%d/%d %d:%02d:%02d @s" %
    [h, min, s, m, d, y % 100, am_pm]
end

At the top of the controller, enter this line:


before_action :get_time

In the layout page application.html.erb above the yield statement, enter these lines:


<p class="r"><%= @time_string %></p>

In the controller specific style file add this line:


p.r { text-align: right }

2. What is a migration?
   Ans: The Rails migrations that we have seen modify a database table: (a) create a table, (b) add a column to a table, (c) remove a column from a table, (d) drop a table entirely.
3. How can you fix a mistake that you made in a migration?
   Ans: If you catch the mistake before you run rake db:migrate, you can simply edit the migration file to correct the mistake. If you run rake db:migrate before you catch the mistake, run rake db:rollback, fix the mistake in the migration file, and run rake db:migrate again.

Project1 Submissions

• Show eight Project 1 submissions.

Nested Routes

• With a scaffold based project that contains a primary model and a secondary model connected by a one-to-many relationship, it sometimes makes sense to define nested routes.
• Look at the Nested Routes Example.
• In you are interested, modify Project 2 to use nested routes (5 points extra credit). Be sure to complete Project 2 without using nested routes first.
• If you intend to get an A in this course, you should consider using nested routes for Project 2.
• The NestedRoutes Example includes a zipfile of the Rails project.