This paper introduces a multi-granularity locking model (MGL) for concurrency control in object-oriented database system briefiy, and presents a MGL model formally. Four lockingscheduling algorithms for MGL are propos...This paper introduces a multi-granularity locking model (MGL) for concurrency control in object-oriented database system briefiy, and presents a MGL model formally. Four lockingscheduling algorithms for MGL are proposed in the paper. The ideas of single queue scheduling(SQS) and dual queue scheduling (DQS) are proposed and the algorithm and the performance evaluation for these two scheduling are presented in some paper. This paper describes a new idea of thescheduling for MGL, compatible requests first (CRF). Combining the new idea with SQS and DQS,we propose two new scheduling algorithms called CRFS and CRFD. After describing the simulationmodel, this paper illustrates the comparisons of the performance among these four algorithms. Asshown in the experiments, DQS has better performance than SQS, CRFD is better than DQS, CRFSperforms better than SQS, and CRFS is the best one of these four scheduling algorithms.展开更多
A Model, called 'Entity-Roles' is proposed in this paper in which the world of Interest is viewed as some mathematical structure. With respect to this structure, a First order (three-valued) Logic Language is ...A Model, called 'Entity-Roles' is proposed in this paper in which the world of Interest is viewed as some mathematical structure. With respect to this structure, a First order (three-valued) Logic Language is constructured.Any world to be modelled can be logically specified in this Language. The integrity constraints on the database and the deducing rules within the Database world are derived from the proper axioms of the world being modelled.展开更多
为了能在监控软件中实时监控数据,系统采用物理内存作为实时数据库的主存储区,在内存中完成对数据的存储、管理和实时操作．使用SQL Server 2000数据库管理历史数据,给出了基于商用数据库组态软件实时数据库的结构.整个系统采用多线程...为了能在监控软件中实时监控数据,系统采用物理内存作为实时数据库的主存储区,在内存中完成对数据的存储、管理和实时操作．使用SQL Server 2000数据库管理历史数据,给出了基于商用数据库组态软件实时数据库的结构.整个系统采用多线程面向对象的编程方法,在查找方法上采用直接定位指针的搜索方法,解决了与Windows操作系统相融合的问题．测试结果表明该系统能达到监控实时性的要求．展开更多
文摘This paper introduces a multi-granularity locking model (MGL) for concurrency control in object-oriented database system briefiy, and presents a MGL model formally. Four lockingscheduling algorithms for MGL are proposed in the paper. The ideas of single queue scheduling(SQS) and dual queue scheduling (DQS) are proposed and the algorithm and the performance evaluation for these two scheduling are presented in some paper. This paper describes a new idea of thescheduling for MGL, compatible requests first (CRF). Combining the new idea with SQS and DQS,we propose two new scheduling algorithms called CRFS and CRFD. After describing the simulationmodel, this paper illustrates the comparisons of the performance among these four algorithms. Asshown in the experiments, DQS has better performance than SQS, CRFD is better than DQS, CRFSperforms better than SQS, and CRFS is the best one of these four scheduling algorithms.
文摘A Model, called 'Entity-Roles' is proposed in this paper in which the world of Interest is viewed as some mathematical structure. With respect to this structure, a First order (three-valued) Logic Language is constructured.Any world to be modelled can be logically specified in this Language. The integrity constraints on the database and the deducing rules within the Database world are derived from the proper axioms of the world being modelled.
文摘为了能在监控软件中实时监控数据,系统采用物理内存作为实时数据库的主存储区,在内存中完成对数据的存储、管理和实时操作．使用SQL Server 2000数据库管理历史数据,给出了基于商用数据库组态软件实时数据库的结构.整个系统采用多线程面向对象的编程方法,在查找方法上采用直接定位指针的搜索方法,解决了与Windows操作系统相融合的问题．测试结果表明该系统能达到监控实时性的要求．
