touch_model_timestamps_unless

# File activerecord/lib/active_record/insert_all.rb, line 171
        def touch_model_timestamps_unless(&block)
          model.send(:timestamp_attributes_for_update_in_model).map do |column_name|
            if touch_timestamp_attribute?(column_name)
              "#{column_name}=(CASE WHEN (#{updatable_columns.map(&block).join(" AND ")}) THEN #{model.quoted_table_name}.#{column_name} ELSE CURRENT_TIMESTAMP END),"
            end
          end.compact.join
        end