【摘要】 从分布式工程设计事务环境和事务管理特点出发 ,给出一种分布式工程数据库系统 (DEDBS)事务管理子系统的体系结构 ,提出一种适用于 DEDBS中的事务两阶段提交协议 ,介绍两种能支持工程设计事务的并发控制方法 :基于 2 PL的扩充分层封锁模型的并发控制方法和改进的乐观并行控制方法更多还原

【Abstract】 Considering the environment of distributed engineering design transaction and the properties of transaction management, an architecture of distributed engineering database system(DEDBS) is given.A transaction two phrase commit protocol which is suitable for DEDBS is proposed. Two concurrency control methods which can support engineering design transaction are also presented. They are the concurrency control method of extended declamination locking model based on 2PL and the improving optimistic concurrency control method.更多还原