| 摘要 |
PURPOSE:To prevent deterioration of the retrieving performance by applying the retrieving processing under the equal mark conditions in an index application mode even in case the retrieving conditions contain a negative operator and an unequal mark. CONSTITUTION:A set arithmetic processing mechanism 106 including codes performs a set of identifiers of data stored in a data storing device 109 and the set arithmetic for a pair of a code that shows whether the data satisfies or not the retrieving conditions. An interactive retrieval control mechanism 105 applies the equivalent change to the retrieving conditions so that each simple logic item includes no unequal mark. The retrieving conditions supplied from an input device 101 receive the equivalent exchange from the mechanism 105 so that each simple logic term includes no unequal mark. Then, the mechanism 106 performs a set arithmetic with codes under the retrieving conditions for a set of identifiers of the data satisfying the simple logic term. Thus it is possible to carry out the effective retrieving with prevention of deterioration of the retrieving performance even in case the retrieving conditions include a negative operator.
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