| As a product of the combination of database and artificial intelligence, the Data mining is the frontier area of the database study and also an important instrument and means to improve the management and strategic ability. Its mission is to collect, from the enormous data, the hidden, unknown knowledge with potential value to the strategies.Rough Set (RS) Theory is a new type of mathematic instrument used to deal with vague and inaccurate problems, mainly applied to the expression, research and induction of incomplete data or uncertain knowledge. The most distinctive feature of RS from other such approaches dealing with uncertain problems as probability, Fuzzy Set and Evidence Theory is that it is unnecessary to provide any a priori knowledge, beyond the data set to be done with — that is, it is unnecessary to provide the subordinate degree and subordinate function, thus avoiding the... |