| 摘要 |
PURPOSE:To attain flexible access with an index and to reduce the load of an auxiliary storage device and a CPU respectively, by using a function to secure dinamically an index area together with production and deletion of the index as necessary. CONSTITUTION:The control is shifted to an index producing mechanism 3 when an access system deciding mechanism 2 decides that no corresponding index is included in a field 31. Then the mechanism 3 sets the using factor of an index 23 at 100% as long as it is decided that sharing and updating are not allowed to the processing state of a file 21. The area size of the index 23 is decided based on the present number of records of the file 21 and a new index control block 13 corresponding to the field 31. is produced. Then the area of the index 23 corresponding to the field 31 is secured and an index is produced. If it is judged by the mechanism 2 that no access is required with the index 23, control is shifted to an index deleting mechanism 6 from an access control mechanism 1. Thus the block 13 and the index 23 are deleted.
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