Harnessing Active Database Abstraction to Support Distributed Workstation-based Applications

传统的dbms是被动的：它们只在用户或应用程序显式请求时执行查询或事务。许多非传统应用程序，如CIM、过程控制、医院监视系统、空中交通控制和办公室工作流控制，需要及时响应（关键）情况，这些被动dbms不能很好地服务于这些应用程序。对于这些应用程序，重要的是监视数据库状态上定义的条件，然后，当这些条件出现时，调用指定的操作。该项目通过以下方式推进了PI先前在活动数据库方面的工作：1)巩固了早期对活动数据库的研究；2)扩展了活动数据库范例，以有效地支持需要分布式工作站配置的非传统应用程序。这个扩展有助于在数据库和一个或多个工作站之间智能地暂存数据，还提供了更新传播机制。为实现上述目标，对分布式状态监测进行了研究。本文的研究结果将使工作站上的应用程序开发人员从管理工作站与数据库之间的共享数据以及维护共享数据的一致性中解脱出来。这项研究的目的是利用活动数据库作为底层抽象，在用户层面提供“分级透明”。

Traditional DBMSs are passive: they execute queries or transactions only when explicitly requested to do so by a user or an application program. Many non-traditional applications, such as CIM, process control, hospital monitoring systems, air traffic control, and office workflow control, which require timely response to (critical) situations are not well served by these passive DBMSs. For these applications, it is important to monitor conditions defined on the states of the database, and then, when these conditions occur, invoke specified actions. This project advances previous work on active databases by the PI by i) consolidating earlier research on active databases and ii) extending the active database paradigm to efficiently support non-traditional applications requiring distributed workstation configuration. This extension helps in intelligently staging the data between the database and one or more workstations and also provides a mechanism for update propagation. Distributed condition monitoring is investigated to achieve the above. The results of this research will relieve the application programmer at the workstation from the management of shared data between the workstation and the database as well as maintaining the consistency of shared data. This research is aimed at providing 'staging transparency' at the user level using active database as an underlying abstraction.