一种新的实现多级安全数据库系统的方法  

A novel implementation for multilevel secure database system

作　　者：刘大昕 崔宾阁 

机构地区：[1]哈尔滨工程大学计算机科学与技术学院,黑龙江哈尔滨150001

出　　处：《哈尔滨工程大学学报》2004年第5期644-648,共5页Journal of Harbin Engineering University

摘　　要：为了解决多级关系实现时存在的重复联接和虚假元组等问题,这里提出了一种新的多级关系分解和恢复算法。该算法采用水平分片的方式将多级关系划分为多个单级关系,并且可以根据需要从这些单级关系中重构多级关系。与SeaView算法相比,该算法不需要对多级关系执行垂直分片,因此它在恢复多级关系时只需要在单级关系集合上执行联合操作,从而提高了多级关系的存取效率并且消除了虚假元组。A new decomposition and recovery algorithm was presented to solve the problems such as repeated joins and spurious tuples in multilevel relation implementation. The algorithm uses horizontal partitions to divide a multilevel relation into several single-level relations, while it can reconstruct the multilevel relation from those single-level relations when necessary. Unlike SeaView algorithm, the algorithm does not divide a multilevel relation vertically, and it restores the multilevel relation based on unions of single-level relations. The algorithm improves multilevel relation access efficiency and eliminates spurious tuples.

关 键 词：多级安全数据库系统 元组 恢复算法 存取效率 分片 操作 重构 单级 联接 消除 

分 类 号：N941[自然科学总论—系统科学] TN792[电子电信—电路与系统]