RIA: Combining Queries and Navigation in Workstation/ServerDatabase Systems

目前的数据库系统技术还不能满足许多应用领域的需求。关系数据库系统（rdbms）擅长提供对大型平面记录集的高级关联（即基于查询的）访问。另一方面，面向对象数据库系统（oodbms）提供了更强大的数据建模功能，但主要支持基于导航的数据访问。这项研究的目标是开发灵活的工作站/服务器数据库系统，使其能够动态地适应各种应用的要求，使这些应用能够利用数据库的能力，并从工作站和局域网价格/性能的持续快速增长中获益。这样的数据库系统将能够根据编译时和运行时考虑，自适应地选择面向查询和面向导航的策略。所采用的方法是扩展最近为面向导航的oodbms开发的技术，使其与更传统的面向查询（关系）方法的技术共存。然而，要实现这一目标，将需要在性能建模和分析、开发新的数据管理算法和新的查询优化技术以及解决许多数据库系统体系结构问题方面进行大量工作。该项目的结果将包括分析数据传递和查询传递之间的权衡、缓存维护算法、查询优化和内存管理，以及基于这些新技术的模拟和实现的详细性能分析。

The needs of many application domains are not met by current database system technology. Relational database systems (RDBMSs) excel at providing high-level, associative (i.e., query-based) access to large sets of flat records. Object-oriented database systems (OODBMSs) on the other hand, provide more powerful data modelling capabilities, but primarily support navigation-based access to the data. The goal of this research is to develop flexible workstation/server database systems which can dynamically adapt to the requirements of a wide range of applications, allowing those applications to exploit database capabilities and benefit from the continuing rapid gains in workstation and local area network price/performance. Such database systems will be able to adaptively choose between query-oriented and navigation-oriented strategies based on both compile-time and runtime considerations. The approach taken will be to extend the techniques that have been recently developed for navigation-oriented OODBMSs to co-exist with techniques from the more traditional query-oriented (relational) approach. To achieve this end, however, will require significant work in performance modeling and analysis, the development of new data management algorithms and new query optimization techniques, and the resolution of numerous database systems architecture issues. The results of this project will include analyses of the tradeoffs between data-shipping and query-shipping, algorithms for cache maintenance, query optimization, and memory management, and detailed performance analyses based on simulation and implementation of these new techniques.