广义投影和外连接  

General Projection and Outerjoin

作　　者：严哲南[1] 楼荣生[1] 

机构地区：[1]复旦大学计算机科学系,上海200433

出　　处：《计算机科学》1999年第6期82-84,共3页Computer Science

摘　　要：In this paper we introduce mainly the relation between general projection and outerjoin and the relation between general projection and semijoin. We also put forward pseudodistributive law of general projection. Then we provide a more mature theory about general projection.In this paper we introduce mainly the relation between general projection and outerjoin and the relation between general projection and semijoin. We also put forward pseudodistributive law of general projection. Then we provide a more mature theory about general projection.

关 键 词：数据仓库 聚合查询 广义投影 外连接 

分 类 号：TP311.13[自动化与计算机技术—计算机软件与理论]