module ActiveRecord::Persistence

ball.touch(:updated_at) # => raises ActiveRecordError
ball = Ball.new

ActiveRecordError will be thrown. For example:
Note that +touch+ must be used on a persisted object, or else an

@brake.touch
# triggers @brake.car.touch and @brake.car.corporation.touch

end
belongs_to :corporation, touch: true
class Car < ActiveRecord::Base

end
belongs_to :car, touch: true
class Brake < ActiveRecord::Base

then +touch+ will invoke +touch+ method on associated object.
If used along with {belongs_to}[rdoc-ref:Associations::ClassMethods#belongs_to]

product.touch(:started_at, :ended_at) # updates started_at, ended_at and updated_at/on attributes
product.touch(:designed_at) # updates the designed_at attribute and updated_at/on
product.touch(time: Time.new(2015, 2, 16, 0, 0, 0)) # updates updated_at/on with specified time
product.touch # updates updated_at/on with current time

attributes. If no time argument is passed, the current time is used as default.
If attribute names are passed, they are updated along with updated_at/on
This method can be passed attribute names and an optional time argument.

+after_commit+ and +after_rollback+ callbacks are executed.
Please note that no validation is performed and only the +after_touch+,
or the time specified.
Saves the record with the updated_at/on attributes set to the current time

def touch(*names, time: nil)
  _raise_record_not_touched_error unless persisted?
  _raise_readonly_record_error if readonly?
  attribute_names = timestamp_attributes_for_update_in_model
  attribute_names |= names.map! do |name|
    name = name.to_s
    self.class.attribute_aliases[name] || name
  end unless names.empty?
  unless attribute_names.empty?
    affected_rows = _touch_row(attribute_names, time)
    @_trigger_update_callback = affected_rows == 1
  else
    true
  end
end