查询评估和近似函数依赖是数据查询和管理中非常重要的两个研究方向。在本文中,基于已经挖掘的近似函数依赖,一个关系被分解成等价的几个子关系。同时,一些基本的查询表达式也相应的被重写,这些重写的查询表达式在执行时所需的时间成本更少。这一方法能让我们以更加有效的方式来处理一些查询问题。
Query evaluation improvement and approximate functional dependencies (AFD) are two important research topics in data query and management. In this paper, the relations are decomposed with respect to the discovered AFDs, and several basic data queries are reformulated in light of expressive equivalence, aimed at reducing time cost. This is helpful for processing queries in an efficient manner.