XN-Store:一种原生XML数据库的存储方案

XN-Store:A Storage Scheme for Native XML Databases

随着XML相关标准的推广与应用,Web上出现了大量的XML文档.为了进行有效的管理,有必要将XML文档存储到数据库中.存储方案已成为XML数据管理领域研究的一个重要课题.将XML文档映射为关系表,存储到传统的RDBMS中,会破坏XML数据的树形结构,造成查询效率的下降.提出了一种新的用于原生XML数据库的存储方案——XN-Store.该方案基于索引结构将XML节点作为记录直接存储到分页文件中,建立起持久化文档对象模型,从而保持了XML数据原有的树形结构.XN-Store不仅降低了XML文档的存储空间开销,而且实现了XML节点的快速串行化输出和访问操作.作为通用的原生XML存储方案,XN-Store支持各种二级索引的创建,以提高XML查询处理的效率.采用多种数据集,分别在XN-Store和先前的XML存储系统上进行实验,比较存储空间、存储时间、串行化时间和节点访问时间.实验结果表明,XN-Store是一种高性能的原生XML数据库存储方案.

With the growing popularity and application of XML related standards,large repositories of XML documents have emerged on the Web.It is necessary to store these documents into a database to make them manageable.Storage schemes have become an important research topic in the XML data management field.Mapping XML documents to relational tables and storing them into a traditional RDBMS will break down the tree structure of XML data and cause a decline in query efficiency.This paper presents a novel storage scheme,called XN-Store,for native XML databases.Based on the index structure,this scheme directly stores XML nodes as records into a paged file to build up the persistent document object model,thus retaining the original tree structure of XML data.XN-Store not only reduces the storage space overhead of XML documents,but also implements the fast serialization and access of XML nodes.As a general purpose native XML storage scheme,XN-Store supports the creation of various secondary indexes to improve the efficiency of XML query processing.Extensive experiments are conducted on XN-Store and several previous XML storage schemes using a range of real and synthetic datasets,comparing the storage space,storage time,serialization time and node access time.The experimental results show that XN-Store is a high performance storage scheme for native XML databases.