Abstract: A data management method includes a reference activation step, after generating a first time-series data for causing chronological relationship to be identifiable in a memory device at activation of a reference operation to a first record in a database, of referring to the first record; an update step, in response to an update request for the first record, of generating a second record corresponding to the first record in the database and updating the second record; a commit step of generating a second time-series data in the memory device at a commit operation for the updating; a reference termination step of deleting the first time-series data at completion of the reference operation; and a deletion step, if the first time-series data generated earlier than the second time-series data is not present as a result of the commit step or the reference termination step, of deleting the first record.

Abstract: A data presentation device with a memory storage area being used without any futility is disclosed.

Abstract: A data management method includes a reference activation step, after generating a first time-series data for causing chronological relationship to be identifiable in a memory device at activation of a reference operation to a first record in a database, of referring to the first record; an update step, in response to an update request for the first record, of generating a second record corresponding to the first record in the database and updating the second record; a commit step of generating a second time-series data in the memory device at a commit operation for the updating; a reference termination step of deleting the first time-series data at completion of the reference operation; and a deletion step, if the first time-series data generated earlier than the second time-series data is not present as a result of the commit step or the reference termination step, of deleting the first record.

Abstract: A database management program capable of restoring a use management book indicating allocation/non-allocation of data to individual unit storage regions, without the need to perform physical initialization at the time of reinitialization. When the database is initialized, all allocation flags provided in the use management book and indicative of allocation/non-allocation of data to the respective unit storage regions are set to a non-allocated state, and the value of an initialization counter indicative of the number of times the database has been initialized is updated. Each time data is allocated to one of the unit storage regions in the database, the allocation flag in the use management book corresponding to the data-allocated unit storage region is set to an allocated state, and the value of the initialization counter is set as an allocation-timed counter value associated with the data-allocated unit storage region.

Abstract: A data presentation device with a memory storage area being used without any futility is disclosed.

Abstract: In a process for managing a plurality of data items contained in a plurality of pages which are sequentially arranged in accordance with predetermined relationships, information on an amount of available space in each of the plurality of pages is stored. When a first data item is inserted into or deleted from a first page among the plurality of pages, an amount of available space in each of second and third pages is acquired based on the above information, where the second page precedes the first page in the sequential arrangement of the plurality of pages, and the third page follows the first page in the sequential arrangement. Before insertion of the first data item into the first page or after deletion of the first data item from the first page, at least one second data item contained in the first page is moved to the second page or the third page according to the amount of available space in each of the second and third pages.

Abstract: A database management program capable of restoring a use management book indicating allocation/non-allocation of data to individual unit storage regions, without the need to perform physical initialization at the time of reinitialization. When the database is initialized, all allocation flags provided in the use management book and indicative of allocation/non-allocation of data to the respective unit storage regions are set to a non-allocated state, and the value of an initialization counter indicative of the number of times the database has been initialized is updated (S2). Each time data is allocated to one of the unit storage regions in the database, the allocation flag in the use management book corresponding to the data-allocated unit storage region is set to an allocated state, and the value of the initialization counter is set as an allocation-timed counter value associated with the data-allocated unit storage region (S3).

Abstract: In a process for managing a plurality of data items contained in a plurality of pages which are sequentially arranged in accordance with predetermined relationships, information on an amount of available space in each of the plurality of pages is stored. When a first data item is inserted into or deleted from a first page among the plurality of pages, an amount of available space in each of second and third pages is acquired based on the above information, where the second page precedes the first page in the sequential arrangement of the plurality of pages, and the third page follows the first page in the sequential arrangement. Before insertion of the first data item into the first page or after deletion of the first data item from the first page, at least one second data item contained in the first page is moved to the second page or the third page according to the amount of available space in each of the second and third pages.