| 摘要 |
PURPOSE:To perform the update and the sequential read dependent upon a linked sequential file in a high speed by providing an external sequence table, which is connected to the table load part and the table write part, in an external file medium. CONSTITUTION:In case of sequential read, record sequential read part 5 refers to internal sequence table 16 and is operated according to its sequence flag. When the flag is ''1'', part 5 refers to records read once and gives the number of records to multiple record read part 12 and instructs read. Read part 12 transfers continuous records read once to block buffer 17, and read part 5 transfers records successively to internal data area 11. When the flag is ''0'', read part 5 reads records while inspecting the next link pointer attendant on records at every one record for one- record unit read part 6. In case of record addition, contents of table 16 are written into external sequence table by table write part 13 according to a file close instruction. |
