数据仓库中一种基于维层次编码的位图索引方法  

Bitmap index based on dimension hierarchical encoding in data warehouse

作　　者：胡孔法[1] 董逸生[2] 陈崚[1] 

机构地区：[1]扬州大学计算机科学与工程系,扬州225009 [2]东南大学计算机科学与工程系,南京210096

出　　处：《东南大学学报（自然科学版）》2005年第2期171-177,共7页Journal of Southeast University：Natural Science Edition

基　　金：国家自然科学基金资助项目 (60473012);国家"十五"重大科技攻关资助项目(2003BA614A);江苏省"十五"高科技资助项目(BG2004034).

摘　　要：为了减少OLAP中的多表连接,压缩维属性连接关键字,对查询数据进行有效地分组聚集操作,来提高OLAP查询速度.利用维属性具有层次特性对维成员进行编码,生成其维层次编码,来代替维表中原关键字,实现了维表关键字的压缩.通过编码长度较小的维层次编码及其层次前缀路径,对维层次编码进行前缀匹配操作,快速检索出与查询关键字相匹配的维层次编码,求得维层次属性的查询范围,从而大大减少和简化了事实表与维表之间的多表连接,减少了I/O开销,提高了OLAP查询效率.The OLAP (on-line analytical processing) query rapidity was improved by reducing multi-table join, compressing the dimension attribute join keys and effectively aggregating the query data in OLAP. In this paper to build dimension hierarchical encoding surrogate key for each dimension member by using the dimension hierarchical characteristic is proposed. By using the small dimension hierarchical encoding and their hierarchical prefix path, this method can rapidly retrieve the matching dimension hierarchical encoding and evaluate the set of query ranges for each dimension. As a result, this method can drastically reduce the multi-table join effort and so much as could remove completely one or more join operations, reduce the disk I/Os, and highly improve the efficiency of OLAP queries.

关 键 词：数据仓库 联机分析处理 位图索引 维层次编码 

分 类 号：TP311[自动化与计算机技术—计算机软件与理论]