method

touch

v4.1.8 - Show latest stable - Class: ActiveRecord::Persistence

touch(name = nil)

public

Saves the record with the updated_at/on attributes set to the current time. Please note that no validation is performed and only the after_touch, after_commit and after_rollback callbacks are executed. If an attribute name is passed, that attribute is updated along with updated_at/on attributes.

product.touch               # updates updated_at/on
product.touch(:designed_at) # updates the designed_at attribute and updated_at/on

If used along with belongs_to then touch will invoke touch method on associated object.

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

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

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

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

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

# File activerecord/lib/active_record/persistence.rb, line 434
    def touch(name = nil)
      raise ActiveRecordError, "cannot touch on a new record object" unless persisted?

      attributes = timestamp_attributes_for_update_in_model
      attributes << name if name

      unless attributes.empty?
        current_time = current_time_from_proper_timezone
        changes = {}

        attributes.each do |column|
          column = column.to_s
          changes[column] = write_attribute(column, current_time)
        end

        changes[self.class.locking_column] = increment_lock if locking_enabled?

        changed_attributes.except!(*changes.keys)
        primary_key = self.class.primary_key
        self.class.unscoped.where(primary_key => self[primary_key]).update_all(changes) == 1
      else
        true
      end
    end

touch

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