| 摘要 |
PURPOSE:To reduce an unnecessary loading and to improve the efficiency of a processing capacity by inhibiting the reading of a data block having no record in a main storage device at the time of accessing data in a data set. CONSTITUTION:When an access request is outputted from a data requesting means 20, an accessing means 30 loads the contents of an entry area 3 constituting an index area 5 and that of a record existence display area to the main storing means 40. The accessing means 30 successively retrieves the entry area 3 loaded to the main storing means 40, loads the contents of a data block 2 stored in a data area 4 to the main storing means 40 correspondingly to said retrieval and accesses a record 1 included in the data block 2 in accordance with a key. When the area 6 displays that there is no record 1 in the data block 2, the accessing means 20 skips the data block having no record 1 to execute the access.
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