摘要
在对Mediator/Wrapper集成系统及其查询特点进行详细分析的基础上,针对涉及多个数据源的连接查询是使用频率较高且是查询代价最高的一种查询方式这一事实,确定了以全局连接查询为主要优化对象,并提出了用半连接方法来优化连接查询。在对半连接执行方案进行优化时,提出了半连接加权有向图的概念,并给出了针对半连接加权有向图的半连接执行方案的快速有效的优化算法。
This paper analyzes the integration system based on Mediator/Wrapper and its feature of query in detail.According to the fact that global join query involving more than several datasources is the main query type and its cost of query is very high,we consider global join query as the main object to be optimized.At the same time,this article puts forward optimization of join query based on semijoin.This paper presents the directed weighted graph of semijoin in order to optimize semijoin execution plan.Furthermore,the fast and effective optimization algorithm is presented in order to produce optimum semijoin execution plan based on directed weighted graph of semijoin.
出处
《计算机工程与应用》
CSCD
北大核心
2007年第12期159-161,242,共4页
Computer Engineering and Applications
