From XML schema to relations: a cost-based approach to XML storage
From XML schema to relations: a cost-based approach to XML storage
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DOI：
10.1109/icde.2002.994698
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发表时间：
2002-08
期刊：
影响因子：
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通讯作者：
Philip Bohannon;J. Freire;Prasan Roy;Jérôme Siméon
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文献类型：
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作者：
Philip Bohannon;J. Freire;Prasan Roy;Jérôme Siméon
随着Web应用程序处理XML的数量不断增加，人们对在关系数据库中存储XML数据的兴趣也越来越大。由于XML树结构的复杂性和平面关系表的简单性之间的不匹配，在RDBMS中存储同一文档有许多方法，并且已经提出了许多启发式技术。这些技术通常定义固定的映射，而不考虑应用程序的特性。然而，固定的映射不可能对所有可能的应用都很好地工作。相比之下，LegoDB是一个基于成本的XML存储映射引擎，它探索可能的XML到关系映射的空间，并为给定的应用程序选择最佳映射。LegoDB利用了当前的XML和关系技术：（1）它用XML模式、XML数据统计和XQuery工作负载对目标应用程序进行建模;（2）通过XML模式重写生成配置空间;（3）使用通过标准关系优化器获得的成本估计来选择派生配置中的最佳配置。我们描述了LegoDB存储引擎，并提供实验结果，证明这种方法的有效性。
As Web applications manipulate an increasing amount of XML, there is a growing interest in storing XML data in relational databases. Due to the mismatch between the complexity of XML's tree structure and the simplicity of flat relational tables, there are many ways to store the same document in an RDBMS, and a number of heuristic techniques have been proposed. These techniques typically define fixed mappings and do not take application characteristics into account. However, a fixed mapping is unlikely to work well for all possible applications. In contrast, LegoDB is a cost-based XML storage mapping engine that explores a space of possible XML-to-relational mappings and selects the best mapping for a given application. LegoDB leverages current XML and relational technologies: (1) it models the target application with an XML Schema, XML data statistics, and an XQuery workload; (2) the space of configurations is generated through XML-Schema rewritings; and (3) the best among the derived configurations is selected using cost estimates obtained through a standard relational optimizer. We describe the LegoDB storage engine and provide experimental results that demonstrate the effectiveness of this approach.