Module | ActiveRecord::Dirty
In: | lib/active_record/dirty.rb

Track unsaved attribute changes.

A newly instantiated object is unchanged:

      person = Person.find_by_name('uncle bob')
      person.changed?       # => false

Change the name:

      person.name = 'Bob'
      person.changed?       # => true
      person.name_changed?  # => true
      person.name_was       # => 'uncle bob'
      person.name_change    # => ['uncle bob', 'Bob']
      person.name = 'Bill'
      person.name_change    # => ['uncle bob', 'Bill']

Save the changes:

      person.save
      person.changed?       # => false
      person.name_changed?  # => false

Assigning the same value leaves the attribute unchanged:

      person.name = 'Bill'
      person.name_changed?  # => false
      person.name_change    # => nil

Which attributes have changed?

      person.name = 'bob'
      person.changed        # => ['name']
      person.changes        # => { 'name' => ['Bill', 'bob'] }

Before modifying an attribute in-place:

      person.name_will_change!
      person.name << 'by'
      person.name_change    # => ['uncle bob', 'uncle bobby']

### Methods

changed changed? changes included

### Public Class methods

included(base)

### Public Instance methods

changed()

List of attributes with unsaved changes.

      person.changed # => []
      person.name = 'bob'
      person.changed # => ['name']

changed?()

Do any attributes have unsaved changes?

      person.changed? # => false
      person.name = 'bob'
      person.changed? # => true

changes()

Map of changed attrs => [original value, new value]

      person.changes # => {}
      person.name = 'bob'
      person.changes # => { 'name' => ['bill', 'bob'] }

[Validate]