An Object Flow Computer for Object-Oriented Database Applications

该项目致力于为大型数据库应用程序设计和评估对象流计算机。这种并行系统的主要特点是：(A)直接支持面向对象的语义关联模型，它可以比现有数据模型更明确地建模复杂数据；(B)使用两阶段查询处理技术，它可以大大减少并行处理机之间传输的数据量；(C)使用基于数据语义特性的垂直分段模型，以提高并发性，最大限度地减少不必要的数据传输；(D)整合若干软件和硬件技术，以解决非常大的数据库管理问题。研究了面向对象处理功能的硬件和软件设计中的性价比权衡问题。面向对象的数据库管理系统具有数据抽象性、继承性、多态、信息隐藏、数据与元数据统一处理等特点。面向对象数据库管理系统的语义建模扩展在支持CAD/CAM、CASE和办公自动化等高级应用方面有着广阔的前景。然而，许多关键技术及其在硬件和软件中的实现还没有被很好地理解。本项目从分析和实验的角度解决了受技术和应用要求制约的设计权衡。开发的成果将导致更有效和更快的面向对象的数据库管理系统。

This project focuses on designing and evaluating an Object Flow Computer for large database applications. The main features of this parallel system are (a) the direct support of an object-oriented semantic association model, which can model complex data more explicitly than existing data models; (b) the use of a two-phase query processing technique, which can drastically reduce the amount of data to be transferred among parallel processors; (c) the use of a vertical fragmentation model based on semantic properties of data, which increases the degree of concurrency and minimizes unnecessary data transfers; and (d) the integration of a number of software and hardware techniques to solve very large database management problems. Research is carried out on analyzing the cost-performance tradeoffs in designing object-oriented processing functions in hardware and software. An object-oriented database management system possesses many desirable features, which include data abstraction, inheritance, polymorphism, information hiding, and uniform treatment of data and meta-data. The extension of object-oriented database management systems with semantic modeling holds great promise in supporting advanced application, such as CAD/CAM, CASE, and office automation. However, many of the essential techniques and their implementation in hardware and software are not well understood. This project addresses the design tradeoffs subject to technological and application requirements from an analytical and experimental points of view. Results developed will lead to more efficient and faster object-oriented database management systems.