Interoperable Query Processing with Networked Heterogeneous Information Servers

本研究探讨异质性网路资讯伺服器间的查询处理。 服务器可以是数据库、图像服务器、WAIS服务器或因特网搜索引擎。 源可以支持OLE（对象链接和嵌入）DB或ODMG/OQL（对象数据管理组/对象查询语言）类接口。 架构基于中介器（基于某种公共数据模型）和包装器（以公共模型和格式提供来自源的答案）。本研究定义了一种高阶包装语言WHOL，以扩展包装技术并支持不能直接对源进行评估的中介查询。 评估WHOL查询的技术开发。 WHOL支持可伸缩性，因为新的（不同的）源被合并，并将包装器扩展到活动的信息代理。灵活的中介查询处理技术的开发，包装的能力范围从简单的参数化功能，以支持复杂的优化和评估引擎。 中介查询处理的成本模型，和语义的查询评估包装不可用的来源，也被开发。 算法开发的包装器查询处理随时间变化的描述，和其他元数据，源。 解决方案将被纳入法国INRIA正在开发的迪斯科架构中。 这项研究将扩展异构网络体系结构中包装器和中介器的能力和可伸缩性

This research investigates interoperable query processing with heterogeneous networked information servers. Servers may be databases, image servers, WAIS servers, or Internet search engines. The sources may support OLE (Object Linking and Embedding) DB or ODMG/OQL (Object Data Management Group/Object Query Language)-like interfaces. Architectures are based on mediators (based on some common data model), and wrappers (that provide answers from sources in the common model and format). This research defines WHOL, a High Order Wrapper Language, to extend wrapper technology and support mediator queries that cannot be directly evaluated against the sources. Techniques for evaluating WHOL queries are developed. WHOL supports scalability, as new (dissimilar) sources are incorporated, and extends wrappers into active brokers of information. Techniques for flexible mediator query processing are developed, for wrappers whose capability ranges from simple parameterized functions, to support complex optimization and evaluation engines. Cost models for mediator query processing, and semantics for query evaluation in wrappers with unavailable sources, are also developed. Algorithms are developed for wrapper query processing with time-varying descriptions, and other meta-data, on sources. Solutions will be incorporated within the Disco architecture being developed in INRIA, France. This research will extend the capability and scalability of wrappers and mediators in heterogeneous networked architectures