How to set default values in Rails?

Question

I\'m trying to find the best way to set default values for objects in Rails.

The best I can think of is to set the default value in the new method in

Answer 1

I needed to set a default just as if it was specified as default column value in DB. So it behaves like this

a = Item.new
a.published_at # => my default value

a = Item.new(:published_at => nil)
a.published_at # => nil

Because after_initialize callback is called after setting attributes from arguments, there was no way to know if the attribute is nil because it was never set or because it was intentionally set as nil. So I had to poke inside a bit and came with this simple solution.

class Item < ActiveRecord::Base
  def self.column_defaults
    super.merge('published_at' => Time.now)
  end
end

Works great for me. (Rails 3.2.x)