影碟租赁系统，影碟分为三类：CD、DVD、VCD，能够这三类影碟实现增加、删除、修改功能，影碟出租后动态的修改库存信息-DVD rental system, video discs are divided into three types: CD, DVD, VCD, DVD to the realization of these three categories to add, delete, modify features, DVD Rental dynamic changes after