关键词: 粗糙集，属性约简，系统嫡，数据库模型，算法复杂度

Abstract: For improving the shortcoming of the model of traditional attribute reductions, some researchers proposed the definitions of attribute reduction based on the system entropy and database model. The main merit of attrbute reduction based on databased model is that it can use the efficient database technology to design the algorithm of attribute reduclion. So the corresponding algorithm of attribute reduction is efficient, For using the efficient database technology to design the algorithm of attribute reduction based on the system entropy, it was proved that the attribute reduction based on the system entropy arc equal to that based on database model. Then the algorithm of attribute reduction based on system entropy with some operations of the database technology was provided. And an example is used to illustrate the new algorithm.

Key words: Rough set, Attribute reduction, System entropy, Database model, Algorithm complexity