A Variable Precision Rough Set Model Based on Database System
基于数据库系统的可变精度粗糙集模型

In this paper rough sets theory is integrated with relational database management systems and instead of the operations of original rough sets relational calculus is taken advantage of.The implementation of calculating approxi- mate core and reduct of available precision rough set model is based on SQL.With the merits of high efficiency of ac- cessing data,using rate of space and applicability for storage of large data sets,compared with data mining performed in flat files,our algorithms is very efficient.