| 摘要 |
PROBLEM TO BE SOLVED: To store data by data structure corresponding to even the reversal of an input data order while maintaining the writing performance of a sparse index, and to retrieve the stored data by a search key. SOLUTION: When the data are stored, offset data which correspond one to one to the respective logic blocks of a data file and show, when a key value within a range of a logic block is in the other logic block, an offset to the other block by unit of logic blocks is stored in addition to data of structure based on the sparse index. In addition, when the data are retrieved, when a record having a desired key value is not found even if an object logic block is retrieved based on an index file, a logic block after the object logic block for the offset shown by the offset data is read, and search is performed for the logic block. COPYRIGHT: (C)2011,JPO&INPIT |
