#109 Tracking Attribute Changes

Rails 2.1 keeps track of the changes you make to a model's attributes. It also allows you to see what the previous value was. But watch out for the gotcha! See this episode for details.

# config/initializers/active_record_settings.rb
ActiveRecord::Base.partial_updates = true

# change tracking methods
p.changed?
p.changed
p.changes
p.name_changed?
p.name_was
p.name_change
p.name_will_change!