type_cast_for_database

# File activerecord/lib/active_record/type/date_time.rb, line 10
      def type_cast_for_database(value)
        return super unless value.acts_like?(:time)

        zone_conversion_method = ActiveRecord::Base.default_timezone == :utc ? :getutc : :getlocal

        if value.respond_to?(zone_conversion_method)
          value = value.send(zone_conversion_method)
        end

        return value unless has_precision?

        result = value.to_s(:db)
        if value.respond_to?(:usec) && (1..6).cover?(precision)
          "#{result}.#{sprintf("%0#{precision}d", value.usec / 10 ** (6 - precision))}"
        else
          result
        end
      end