| 关系模式中候选码的求解 |
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| 引用本文： | 张永,顾国庆. 关系模式中候选码的求解[J]. 上海电力学院学报, 2002, 18(1): 38-40 |
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| 作者姓名： | 张永 顾国庆 |
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| 作者单位： | 上海理工大学,计算机工程学院,上海,200093 |
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| 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。
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| 关 键 词： | 关系模式 候选码 闭包 函数依赖 关系数据库 |
| 文章编号： | 1006-4729(2002)01-0038-03 |
| 收稿时间： | 2001-05-22 |
| 修稿时间： | 2001-05-22 |
Evaluation to Candidate Keys to Relational Model |
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| ZHANG Yong and GU Guo qing. Evaluation to Candidate Keys to Relational Model[J]. Journal of Shanghai University of Electric Power, 2002, 18(1): 38-40 |
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| Authors: | ZHANG Yong and GU Guo qing |
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| Affiliation: | College of Copmputing Engineering, Uninversity of Shanghai for Science and Technology, Shanghai 200093, China;College of Copmputing Engineering, Uninversity of Shanghai for Science and Technology, Shanghai 200093, China |
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| 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. |
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| Keywords: | relational model candidate key closure functional dependency |
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