基于视图机制和分组统计实现SQL中全称量词的转换  

Implementation of Transformation of Universal Quantifier in SQL Based on View Mechanism and Statistical Analysis

作　　者：杨艳[1] 赵雪琴[2] 

机构地区：[1]中原工学院,郑州450007 [2]郑州大学西亚斯国际学院,新郑451150

出　　处：《现代计算机》2014年第11期42-43,52,共3页Modern Computer

摘　　要：SQL语言不支持全称量词,当查询涉及"全部"语义时,需要将全称量词等价转换为存在量词,转换及量词的使用都是难点,需要有相关的逻辑推理及思维能力,从而使程序员难以理解。基于视图机制和分组统计来实现对全称量词的对应语义的转换,思路清晰,容易掌握。SQL language does not support universal quantifier. When a query involves ＂all＂ semantics, it is necessary to transform the universal quantifier into the existential quantifier, which is equivalent. It is difficuh to use conversion and quantifiers, It needs some relevant logic reasoning and thinking ability. Thus it is difficult for programmer to understand them. Based on the view and statistical analysis to realize the replacement of the semantic correspondence of the universal quantifier. It is clarity of thought and it is easy to master.

关 键 词：全称量词 等价转换 视图 分组统计 

分 类 号：TP311.13[自动化与计算机技术—计算机软件与理论]