Timer

I propose to append timers - procedures like triggers, several parameters are specified at creating of them: from which date-and-time ('start') and to which date-and-time ('end') timer is active (timer does not deleted from database after end of this time), length of interval of time ('per'), on which timer is called one or several times, and also displacements of time of call ('schedule') inside interval of time.

create timer timer_name
  start datetime_a
  end datetime_b
  schdule (time1, time2, time3, time4, time5) per delta_time;

create timer ... schedule (0) per 24 hours;

Dmitry Turin