1. A database management program for managing allocation/non-allocation of data to individual unit storage regions of a database by means of a use management book, wherein the database management program causes a computer, when the database is initialized, to set all of allocation flags provided in the use management book and indicative of allocation/non-allocation of data to the respective unit storage regions to a non-allocated state, and to update a value of an initialization counter indicative of a number of times the database has been initialized, and causes the computer, each time data is allocated to one of the unit storage regions in the database, to set the allocation flag in the use management book corresponding to the data-allocated unit storage region to an allocated state, and to set the value of the initialization counter as an allocation-timed counter value associated with the data-allocated unit storage region.