【摘要】 在数据库系统中,数据访问技术从连接模型发展到断开连接模型。在断开连接数据访问模型下,如何进行并发控制,保持数据库一致性,同时提高系统的运行效率,很少有相关的文献进行研究。断开连接访问模型技术自身的优点为有别于传统严格一致的可串行化并发控制协议提供了必要性和可能性。通过剖析断开连接数据访问模型ADO.NET基础上,提出了一种基于时间戳验证的两阶段封锁多版本并发控制协议。该协议解决了在断开连接访问模型下网络数据库系统的并发访问异常,保证了数据的一致性,提高了系统的性能和并发度。最后设计了测试系统,对该协议的性能进行了测试,并与其它协议进行了比较,分析了实验结果,结果表明该协议性能良好。更多还原

【Abstract】 Data access technology develops from connection model to disconnection model in the database system.It is necessary to be resolved that how to do the concurrency control,keep data consistency and enhance running efficient under the disconnection model in the application development.But little research work has been done.The advantage of the disconnection model provides requirement and possibility.In anatomy of ADO.NET,we present a timestamp validation-based two-phase locking multiversion protocol.The protocol resolves concurrenct-access anomalies under the disconnection data access model,ensures data consistency and improve performance and concurrency degree.Finally,we design and realize the test system,compare it with other related protocols and analyze the results.The experiments show that the protocol performs well as expected.更多还原