说明：  1）订票：若该航次余票大于等于乘客订票数，则在该航次的乘客表中，插入订票乘客的信息项，并修改该航次有关数据，否则给出相应信息。 （2）退票：若该航次当前退票数小于等于乘客原订票数，则在相应的乘客表中找到该乘客项，修改该航次及乘客表中有关数据；当某乘客由于退票使订票数为零时，则从乘客表中撤消该数据项。
(1) Booking: If greater than or equal to the cruise passengers booking tickets over the number of passengers in the form of the voyage, passengers booking information insert items, and modify the data of the voyage, or given the appropriate information. (2) Refund: If the voyage is less than the current refund equal to the number of passengers scheduled to vote, then the passengers in the corresponding entry in the table to find the passengers, the voyage and the passengers to modify the data in the table when a passenger booking the refund to number is zero, from passengers to cancel the data entry table.)