Question

What is the Rails way of implementing a view for a data model that contains elements with a has_many/belongs_to relationship?

Here is the model I want to show in list form:
Driver

class Driver < ActiveRecord::Base
  ...
  has_many :cars
end

Here is the model that should be listed underneath each driver:

Car

class Car < ActiveRecord::Base
  ...
  belongs_to :driver
end

I want to show a list of drivers with their respective cars.

This raises two questions:

1 . How do I most efficiently list both in one page? What would my controller and view have to look like? If I simply do

    @drivers = Driver.all

I do not seem to get access to the cars in the view.

2 . If I only list the drivers, and load the cars upon request using AJAX, would I use a cars_controller and a drivers_controller? How would I approach writing tests for this scenario?

Answer 1

Expanding on what you already have:

//controller
  @drivers = Driver.all

  //view
  @drivers.each do |d|
   puts d.messages
   # OR
   d.messages.each do |m|
    puts m.title
   end
  end

The same can be done inversely with @cars = Car.all.