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投稿时间:2001-05-22
投稿时间:2001-05-22
中文摘要: 关系数据库模型的应用十分广泛,其候选码的求解已被证明是一个NP完全问题,从闭包的角度讨论了如何求解候选码,并对其求解过程进行了一定程度的优化.最后提出了一些比较合理的建议.
Abstract:Relational database model is used widely. It is proved that finding all candidate keys of a relational model is an NP problem. This artical mainly discusses how to evaluate all candidate keys to a relational model by using closures, and optimizes the finding procedures to a certain extent, finally also proposes some advice on evaluating the candidate keys.
文章编号:20020109 中图分类号: 文献标志码:
基金项目:
引用文本:
张永,顾国庆.关系模式中候选码的求解[J].上海电力大学学报,2002,18(1):38-40.
ZHANG Yong,GU Guo qing.Evaluation to Candidate Keys to Relational Model[J].Journal of Shanghai University of Electric Power,2002,18(1):38-40.
张永,顾国庆.关系模式中候选码的求解[J].上海电力大学学报,2002,18(1):38-40.
ZHANG Yong,GU Guo qing.Evaluation to Candidate Keys to Relational Model[J].Journal of Shanghai University of Electric Power,2002,18(1):38-40.