| 摘要 |
PROBLEM TO BE SOLVED: To provide a data retrieving method which does not consume many storage areas and can select data meeting retrieval conditions in a short time even if the retrieval conditions dynamically change. SOLUTION: Mask information showing whether or not registered data are an object to be retrieved, is generated and only when it is judged from the mask information that the registered data are the object to be retrieved, a collation is made. An object to be retrieved and collated is limited with the mask information, so the retrieval is carried out in a short time. When it is judged from the mask information that the data are the object to be retrieved, next collation candidate data are selected out of pieces of registered data. It is decided whether or not the retrieval conditions are met according as how much the collation data and collation candidate data match each other. The mask information can be generated from previously registered attribute information and a log that an application program sends. Further, it may be generated from a past access history by totalizing the log. The mask information can be synthesized through logical operation.
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