# module ActiveRecord::Timestamp

# Active Record Timestamp¶ ↑

Active Record automatically timestamps create and update operations if the table has fields named `created_at/created_on` or `updated_at/updated_on`.

Timestamping can be turned off by setting:

    config.active_record.record_timestamps = false

Timestamps are in UTC by default but you can use the local timezone by setting:

    config.active_record.default_timezone = :local

## Time Zone aware attributes¶ ↑

Active Record keeps all the `datetime` and `time` columns timezone aware. By default, these values are stored in the database as UTC and converted back to the current `Time.zone` when pulled from the database.

This feature can be turned off completely by setting:

    config.active_record.time_zone_aware_attributes = false

You can also specify that only `datetime` columns should be time-zone aware (while `time` should not) by setting:

    ActiveRecord::Base.time_zone_aware_types = [:datetime]

You can also add database specific timezone aware types. For example, for PostgreSQL:

    ActiveRecord::Base.time_zone_aware_types += [:tsrange, :tstzrange]

Finally, you can indicate specific attributes of a model for which time zone conversion should not applied, for instance by setting:

    class Topic < ActiveRecord::Base
      self.skip_time_zone_conversion_for_attributes = [:written_on]
    end

### Public Instance Methods

all_timestamp_attributes_in_model() click to toggle source

    # File lib/active_record/timestamp.rb, line 64
    def all_timestamp_attributes_in_model
      timestamp_attributes_for_create_in_model + timestamp_attributes_for_update_in_model
    end

current_time_from_proper_timezone() click to toggle source

    # File lib/active_record/timestamp.rb, line 76
    def current_time_from_proper_timezone
      default_timezone == :utc ? Time.now.utc : Time.now
    end

timestamp_attributes_for_create() click to toggle source

    # File lib/active_record/timestamp.rb, line 68
    def timestamp_attributes_for_create
      ["created_at", "created_on"]
    end

timestamp_attributes_for_create_in_model() click to toggle source

    # File lib/active_record/timestamp.rb, line 56
    def timestamp_attributes_for_create_in_model
      timestamp_attributes_for_create.select { |c| column_names.include?(c) }
    end

timestamp_attributes_for_update() click to toggle source

    # File lib/active_record/timestamp.rb, line 72
    def timestamp_attributes_for_update
      ["updated_at", "updated_on"]
    end

timestamp_attributes_for_update_in_model() click to toggle source

    # File lib/active_record/timestamp.rb, line 60
    def timestamp_attributes_for_update_in_model
      timestamp_attributes_for_update.select { |c| column_names.include?(c) }
    end

### Private Instance Methods

_create_record() click to toggle source
Calls superclass method

    # File lib/active_record/timestamp.rb, line 83
    def _create_record
      if record_timestamps
        current_time = current_time_from_proper_timezone

        all_timestamp_attributes_in_model.each do |column|
          if !attribute_present?(column)
            write_attribute(column, current_time)
          end
        end
      end

      super
    end

_update_record(*args, touch: true, **options) click to toggle source
Calls superclass method

    # File lib/active_record/timestamp.rb, line 97
    def _update_record(*args, touch: true, **options)
      if touch && should_record_timestamps?
        current_time = current_time_from_proper_timezone

        timestamp_attributes_for_update_in_model.each do |column|
          next if will_save_change_to_attribute?(column)
          write_attribute(column, current_time)
        end
      end
      super(*args)
    end

clear_timestamp_attributes() click to toggle source

Clear attributes and changed_attributes

    # File lib/active_record/timestamp.rb, line 138
    def clear_timestamp_attributes
      all_timestamp_attributes_in_model.each do |attribute_name|
        self[attribute_name] = nil
        clear_attribute_changes([attribute_name])
      end
    end

max_updated_column_timestamp(timestamp_names = self.class.send(:timestamp_attributes_for_update)) click to toggle source

    # File lib/active_record/timestamp.rb, line 129
    def max_updated_column_timestamp(timestamp_names = self.class.send(:timestamp_attributes_for_update))
      timestamp_names
        .map { |attr| self[attr] }
        .compact
        .map(&:to_time)
        .max
    end

should_record_timestamps?() click to toggle source

    # File lib/active_record/timestamp.rb, line 109
    def should_record_timestamps?
      record_timestamps && (!partial_writes? || has_changes_to_save?)
    end