Abstract: A method for arranging appointments in an appointment schedule is to be implemented by a computer storing data that includes a session including a plurality of time slots. The data further includes a plurality of cumulative values corresponding respectively to the time slots and a plurality of maximum values related respectively to the cumulative values. The method includes steps of: in response to receipt of a message for reserving a desired time slot selected from among the time slots, changing the cumulative value and the maximum value that correspond to the desired time slot respectively to a first value and a second value; and performing procedures to update the appointment data related to two groups of the time slots that are in the reservation session and that are respectively after the desired time slot and before the desired time slot.