Using ActiveRecord, is there a way to get the old values of a record during after_update

Question

Setup using a simple example: I\'ve got 1 table (Totals) that holds the sum of the amount column of each record in a second table (

Answer 1

To get all changed fields, with their old and new values respectively:

person = Person.create!(:name => 'Bill')
person.name = 'Bob'
person.save
person.changes        # => {"name" => ["Bill", "Bob"]}