Ruby on rails, Change a column value when updating a different column value

Question

I have two columns connected to each other in the Rails model:

Article.body Article.body_updated_on 

I want to change Article.body_updated_on to Time.now , every time Article.body updated. If there should be nothing other updated fields.

Answer 1

Just add before saving the callback to the article model

 class Article < ActiveRecord:Base before_save :update_body_modified private # <--- at bottom of model def update_body_modified self.body_updated_on = Time.now if body_changed? end end 

Answer 2

You can either override the default installer for the body, or even better, use callback to install it just before the update. You can choose one of several options: before_save, before_update ... depending on when you want.

  before_save do |article| article.body_updated_on = Time.now if article.body_changed? end