Count the number of belongs_to

Hi, Jake White:

I recommend using size instead and also consider counter caching instead. This will allow you to speed up the querying of the amount of items of a todo_list considerably (along with using indexes of course).

class TodoList < ActiveRecord::Base 
   has_many :todo_items 
end

class TodoListItems < ActiveRecord::Base 
  belongs_to :todo_list, counter_cache: true, touch: true 
end 

Then with rake you would do the following to todo_list :

rails g migration AddTodoItemsCounterCacheToTodoList todo_list_items_count:integer 

You then should double check to see if the following occurred inside the migration

add_column :todo_lists, :todo_list_items_count, :integer 

If you need to be more specific about what this value is called, you can pass in the the name of what you want the counter cache to be called as a symbol instead of true : counter_cache: :list_count.

For more information, especially the fact you are a beginner, is to read the official Rails Guide on associations.

In general, I highly recommend reading the complete guide at least once.

With every release, I always go out my way to read all the updated guides at least once affected by the new release and review the other guides at least once a quarter.