| 摘要 |
PURPOSE:To improve processing efficiency by managing a secondary index by allowing a main key and a record address of data to correspond each other at every sub-key, retrieving a secondary index by its sub-key with respect to a retrieval processing request based on the sub-key, and obtaining an address. CONSTITUTION:An index file 8 contains a secondary index file 8 and a main file 11, and to a secondary index 10 of the file 9, a main key corresponding to a sub-key, and a record address of data are given in advance, and on the file 11, a main index 12 and a data part 13 are provided. When a user designates the sub-key and requests a reference processing of the data to a file managing part 14, a secondary index retrieving part 15 refers to the index 10 and converts a designated sub-key to a record address. Also, by using it, a data retrieving part 16 executes an access to the data part 13, and when its main key and a main key from the index 10 coincide with each other, it is decided to be proper.
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