摘要
1引言
F. F.Codd于七十年代提出了著名的关系数据库模型,经过几十年发展,以它为基础的关系数据库系统得到了广泛的流行和认可,它有着层次模型和网状模型无可比拟的优点,如灵活性、逻辑和物理独立性、数据完整性等.然而,它也有自身的不足,就是对于不确定性的数据处理能力较差.
: In this paper, Rough Relational Database Model (RRDM) and several ways for extending relational database model (RDM) are introduced at first. Based on literature [2],some different definitions of RRDM and its relational operations are developed then. Some basic properties are discussed also. Finally, the difference and relationship between RRDM and RDM are studied,some interesting results of RRDM and some problems that are studied further in the future are presented.
出处
《计算机科学》
CSCD
北大核心
2002年第7期72-74,89,共4页
Computer Science
基金
本文得到国家自然科学基金(No.69803014)
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