高扩展性XML关键字查询处理技术

XML keyword search is one of the hot research issues for XML data management. However, all these techniques are still not applicable in practice, because of the existing of the contradiction between many types of query semantics and single function of existing systems.. This project tries at erecting a bridge between the technical achievements and the practical applications, and focuses on key techniques of a practical XML keyword search system, including (1) large-scale-XML-data oriented query hinting and result suggesting strategy in real time, such that to provide users quickly feedback with candidate keyword queries and relevant query results, and to avoid users’ workload in repeatedly inputting and submitting keyword queries; (2) flexible and scalable labeling and indexing strategy, such that to reduce the cost of implementing and maintaining the whole system; (3) implementing various algorithms for different query semantics based on this labeling and indexing strategy, and at the same time, supporting efficient algorithms on different subtree result construction, ranking and result presentation; (4) efficient parallel algorithms for XML keyword query processing. This research can greatly advance the current techniques on XML keyword search, the research achievements can greatly enhance the friendliness, usability, efficiency and utilization ratio of an XML keyword search system, and at the same time, set up the theoretical basis and provide technical support for practical XML keyword query processing, which has important research value and application prospects.

关键字查询处理是XML数据管理领域研究的热点问题之一，然而截至目前，XML关键字查询相关的技术仍存在语义多样性和功能单一性的矛盾，严重妨碍了相关技术的应用。本课题以XML关键字查询技术实用化为目标，研究高可扩展性XML关键字查询处理系统所涉及到的一系列关键问题，包括（1）基于大规模XML数据的实时查询提示和结果提示策略，可以给用户提供实时反馈，避免用户反复输入和提交查询；（2）支持灵活性和扩展性的数据编码和索引组织策略，降低系统的实现和维护代价；（3）基于单一编码和索引，支持不同语义及其关系操作、支持各种子树构建、排序和展示的高效算法；（4）高效的并行执行策略。对于XML关键字查询处理系统而言，本项目所研究和解决的问题可在增强其友好性、可用性的同时，提高其执行效率和信息利用率，为XML关键字查询技术的实用化奠定理论基础、提供技术支撑，具有重要的研究价值和应用前景。

本项目通过四年的研究工作，完成了项目设定的研究目标。提出了基于单一编码和结构的、支持不同语义的XML关键字查询处理方法；针对结果子树种类多、构建困难的问题，提出基于用户需求的高效结果子树构建方法极其并行处理策略；提出了若干加速查询处理的算法，并通过丰富的实验对所提出方法的高效性和有效性进行了验证。对于XML关键字查询处理系统而言，项目所研究和解决的问题可在增强其友好性、可用性的同时，提高其执行效率和信息利用率，为XML关键字查询技术的实用化奠定理论基础、提供技术支撑，具有重要的研究价值和应用前景。