数据仓库查询处理中的一种多表连接算法

摘要

Multi-Table join is a common operation for evaluating OLAP queries posed to a data warehouse. The performance of this multi-table join is one of the key problems in the research of data warehouses. Based on the Star Schema for a data warehouse, this paper introduces a new algorithm M-Join for the multi-table join. Compared with the traditional multi-table join processing by the Relational Database Management System, this new algorithm, taking adequate considerations on the characteristics of the data in a data warehouse environment, completes the join by scanning every table only once, thus greatly improves the performance of OLAP query processing. The paper presents and analyzes the experimental results of this comparison.%在进行数据仓库的OLAP(online analytical processing,联机分析处理)查询处理时，经常会涉及到多表连接操作，因此,提高多表连接的性能就成了数据仓库领域的关键性问题.基于数据仓库的星型模式,给出了一种新的多表连接算法(M-Join).与传统关系数据库管理系统的多表连接查询处理相比,该算法充分考虑了数据仓库中的数据本身和多表连接的特点,采用对多个表进行一次性连接的方法,使得查询的性能有明显的改善.同时，还给出了算法的实验结果和分析.