# File activerecord/lib/active_record/attribute_methods/dirty.rb, line 100
def attribute_before_last_save(attr_name)
  mutations_before_last_save.original_value(attr_name.to_s)
end

Returns the original value of an attribute before the last save.

This method is useful in after callbacks to get the original value of an attribute before the save that triggered the callbacks to run. It can be invoked as name_before_last_save instead of attribute_before_last_save("name").

# File activerecord/lib/active_record/attribute_methods/dirty.rb, line 142
def attribute_change_to_be_saved(attr_name)
  mutations_from_database.change_to_attribute(attr_name.to_s)
end

Returns the change to an attribute that will be persisted during the next save.

This method is useful in validations and before callbacks, to see the change to an attribute that will occur when the record is saved. It can be invoked as name_change_to_be_saved instead of attribute_change_to_be_saved("name").

If the attribute will change, the result will be an array containing the original value and the new value about to be saved.

# File activerecord/lib/active_record/attribute_methods/dirty.rb, line 154
def attribute_in_database(attr_name)
  mutations_from_database.original_value(attr_name.to_s)
end

Returns the value of an attribute in the database, as opposed to the in-memory value that will be persisted the next time the record is saved.

This method is useful in validations and before callbacks, to see the original value of an attribute prior to any changes about to be saved. It can be invoked as name_in_database instead of attribute_in_database("name").

# File activerecord/lib/active_record/attribute_methods/dirty.rb, line 181
def attributes_in_database
  mutations_from_database.changed_values
end

Returns a hash of the attributes that will change when the record is next saved.

The hash keys are the attribute names, and the hash values are the original attribute values in the database (as opposed to the in-memory values about to be saved).

# File activerecord/lib/active_record/attribute_methods/dirty.rb, line 171
def changed_attribute_names_to_save
  mutations_from_database.changed_attribute_names
end

Returns an array of the names of any attributes that will change when the record is next saved.

# File activerecord/lib/active_record/attribute_methods/dirty.rb, line 165
def changes_to_save
  mutations_from_database.changes
end

Returns a hash containing all the changes that will be persisted during the next save.

# File activerecord/lib/active_record/attribute_methods/dirty.rb, line 159
def has_changes_to_save?
  mutations_from_database.any_changes?
end

Will the next call to save have any changes to persist?

# File activerecord/lib/active_record/attribute_methods/dirty.rb, line 57
def reload(*)
  super.tap do
    @mutations_before_last_save = nil
    @mutations_from_database = nil
  end
end

reload the record and clears changed attributes.

# File activerecord/lib/active_record/attribute_methods/dirty.rb, line 90
def saved_change_to_attribute(attr_name)
  mutations_before_last_save.change_to_attribute(attr_name.to_s)
end

Returns the change to an attribute during the last save. If the attribute was changed, the result will be an array containing the original value and the saved value.

This method is useful in after callbacks, to see the change in an attribute during the save that triggered the callbacks to run. It can be invoked as saved_change_to_name instead of saved_change_to_attribute("name").

# File activerecord/lib/active_record/attribute_methods/dirty.rb, line 78
def saved_change_to_attribute?(attr_name, **options)
  mutations_before_last_save.changed?(attr_name.to_s, **options)
end

Did this attribute change when we last saved?

This method is useful in after callbacks to determine if an attribute was changed during the save that triggered the callbacks to run. It can be invoked as saved_change_to_name? instead of saved_change_to_attribute?("name").

Options

from When passed, this method will return false unless the original value is equal to the given option

to When passed, this method will return false unless the value was changed to the given value

# File activerecord/lib/active_record/attribute_methods/dirty.rb, line 110
def saved_changes
  mutations_before_last_save.changes
end

Returns a hash containing all the changes that were just saved.

# File activerecord/lib/active_record/attribute_methods/dirty.rb, line 105
def saved_changes?
  mutations_before_last_save.any_changes?
end

Did the last call to save have any changes to change?

# File activerecord/lib/active_record/attribute_methods/dirty.rb, line 128
def will_save_change_to_attribute?(attr_name, **options)
  mutations_from_database.changed?(attr_name.to_s, **options)
end

Will this attribute change the next time we save?

This method is useful in validations and before callbacks to determine if the next call to save will change a particular attribute. It can be invoked as will_save_change_to_name? instead of will_save_change_to_attribute?("name").

Options

from When passed, this method will return false unless the original value is equal to the given option

to When passed, this method will return false unless the value will be changed to the given value