关于数据库信息查询项目数的计算

On Calculation for Inquiry About Items of Information at a Data Base

本文简述了关系数据库特征的数学描述,着重讨论了数据库信息查询项目数的计算问题。

In this paper. the brief mathemetical description of relation data base characteristics has been given. It puts emphasis on the calculating items of inquiry about information at a data base.