| 摘要 |
PURPOSE:To reduce the area size of an index in case of many data records and a small number of types of value secured for an index key, by obtaining the address of the data corresponding to a supplied index key via a bit map access mechanism. CONSTITUTION:A data processing system has a request for return of the address of the data record having the value (b) of an index field 20 out of those data records stored in a data file 10. Thus the control is shifted to a data access mechanism 1 and an index access mechanism 2. Then an access is supplied to an index 30 so that the address of a bit map 70 having the address information on the data record having the value (b) of the field 20 is obtained. Then the control is shifted to a bit map access mechanism 3 and an access is given to the map 70. Thus the address of the data record having the value (b) of the field 20 is obtained and sent back to the data processing system.
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