Track dirty for not-persisted attribute in an ActiveRecord object in rails

Question

I have an object that inherits from ActiveRecord, yet it has an attribute that is not persisted in the DB, like:

 class Foo < ActiveRecord::Base
   attr_acces         


        

Answer 1

Write the bar= method yourself and use an instance variable to track changes.

def bar=(value)
  @bar_changed = true
  @bar = value
end

def bar_changed?
  if @bar_changed
    @bar_changed = false
    return true
  else
    return false
  end
end