International Business Machines Corporation

Ichiroh Teshima

Shigeko Mori

Toshikazu Takahashi

A database management system for determining consistency in a hierarchical database sequentially reads pointers of a plurality of segment data, generates an address hash value, which is a hash value of retention addresses of the segment data having been read, generates a pointer hash value, which is a hash value of the pointers included in the segment data having been read, corrects the address hash value, when the contents of the address already read is updated, based a retention address of segment data added or deleted by the update, corrects the pointer hash value based on each pointer changed by the update, and determines that the hierarchical database is consistent if the corrected address hash value coincides with the corrected pointer hash value.

Database management system, database management method, and program

The invention efficiently determines consistency of a database by a system including a reading section that sequentially reads from the respective segment data included in the database pointers to other segment data, an address recording section that records storage addresses of segment data from which the pointers have been read by the reading section, and a pointer recording section that records the pointers read by the reading section. Then, when segment data is updated in an area in which the pointer reading has been completed, a storage address recorded in the address recording section is modified and a pointer recorded in the pointer recording section is modified. Then, it is determined that the database is consistent on condition that the respective storage addresses recorded in the address recording section coincide with the respective pointers recorded in the pointer recording section.

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Chofu, Japan

Ichiroh Teshima