一个基于XML数据仓库系统的设计与实现

黄土高原数据仓库系统以分布式数据仓库为核心,包含多个异质数据源。系统采用中间件技术不仅提供多层次资源查询服务,并且还使用数据挖掘技术和信息检索技术对资源数据进行深加工,能够主动地为用户提供黄土高原生态环境咨询、评测、预测与决策支持服务。论文重点介绍了一种基于XML的统一模式查询语言———XUSQL,用以解决多数据源中多模式数据融合问题。XUSQL使得在数据仓库中的查询与数据源模式无关,把数据源和数据仓库隔离开,从而有利于构造分布式数据仓库,便于异质数据源之间数据融合以及数据源本身的结构调整。

Design and Realization of a Data Warehouse System Based on XML

The Loess Plateau data warehouse system is a distributed data warehouse including several heterogeneous da-ta sources.This system uses middle wares to supply multi-hierarchy resources query service and apply data mining and information retrieval techniques to process resources data so that users can get active services of querying,suggesting,assessing,or decision making about the Loess Plateau ecological environment.The data warehouse need fetch data from distributed data sources,those maybe be in different data scheme ,therefore we have to use several similar SQL sen-tences though that is lower efficient and the data source scheme must be fixed,nothing can be altered.In fact,in data warehouse not only data but also data scheme may get change sometimes.We present XML-based Uniform Scheme Query Language(XUSQL)to solve this issue.XUSQL uses XML to rebuild conventional SQL,in order to isolate the data warehouse and data sources,make the data sources scheme transparent to the data warehouse query.A uniform scheme of all tables(data)written in XML is stored in data warehouse,which is translated to local scheme by XSLT on data sources.XUSQL is a facility of distributed data warehouse and fusion of data from heterogeneous data sources.