基于聚类的非一致性数据库聚集查询重写  

Aggregation Query Rewritings Based on Clusters in Inconsistent Databases

作　　者：谢东[1] 杨路明[1] 蒲保兴[1] 刘波[1] 

机构地区：[1]中南大学信息科学与工程学院,湖南长沙410083

出　　处：《小型微型计算机系统》2008年第6期1104-1108,共5页Journal of Chinese Computer Systems

基　　金：湖南省教育厅科研基金项目(0Cc671)资助;中南大学创新基金项目(ZB018)资助

摘　　要：在聚类和非一致性数据库无聚集查询基础上提出聚集查询重写方法.通过聚集值范围限定了最值和期望值,给出无连接和有连接的聚集查询重写策略.聚集重写查询通过分析聚类中可能元组和分组属性来过滤聚类,计算初始分组属性的最值和期望值.实验使用TPC-H决策支持基准进行性能研究,分析了聚类基数和数据库尺寸等因素的影响.结果显示尽管重写查询显著地比初始查询的执行时间长,但还是可以接受的,表明方法是有效的.This paper presents the rewriting method for aggregation queries based on clusters and non-aggregation queries in inconsistent databases. The expectation and the extremum are limited by range of aggregation values to propose non-join and join rewriting strategies for aggregation queries. The aggregation rewritten queries analyze potential tuples of clusters and grouping attributes to filter clusters and calculate the expectation and the extremum of original grouping attributes. The experiment presents a performance study using the data and queries of the TPC-H decision support benchmark, and analyzes some effects of relative factors such as the cluster cardinality and database size. Although the experiment results show that rewritten queries are longer than original queries for run time, the run time may be accepted and the method is effective.

关 键 词：关系数据库 非一致性数据库 聚集查询重写 聚类概率 

分 类 号：TP311.132.3[自动化与计算机技术—计算机软件与理论]