| 函数依赖的几种形式定义 |
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| 引用本文： | 张训锋.函数依赖的几种形式定义[J].新疆师范大学学报(自然科学版),1998(4). |
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| 作者姓名： | 张训锋 |
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| 作者单位： | 伊犁州广播电视大学计算中心 伊犁，835000 |
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| 摘 要： | 本文基于语义贴近度,导出并讨论了经典函数依赖(FD)的四种等价形式定义,在此基础上,得到模糊函数依赖(FFD)的两个等价的强依赖定义和两个有序包容的弱依赖定义,证明了FFD的最弱依赖相应于Armstrong公理的有效性和完备性。
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| 关 键 词： | 关系数据库 语义贴近度 函数依赖 强依赖 弱依赖 |
SEVERAL FORMAL DEFINITIONS ABOUT THE FUNCTION DEPENDENCY |
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| Zhang Xunfeng Centre of Computer,YiLi Radio and TV University,Yi Li.SEVERAL FORMAL DEFINITIONS ABOUT THE FUNCTION DEPENDENCY[J].Journal of Xinjiang Normal University(Natural Sciences Edition),1998(4). |
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| Authors: | Zhang Xunfeng Centre of Computer YiLi Radio and TV University Yi Li |
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| Institution: | Zhang Xunfeng Centre of Computer,YiLi Radio and TV University,Yi Li,835000 |
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| Abstract: | In this paper,four definitions of classical function dependency (FD)are induced,and discussed. On the basis of those,two definitions of fuzzy strong function depen-dency(FDFD) ,the two definitions of fuzzy week function dependency(FWFD)are given. It is proved that two FDFDs are each other equality,and two FWFDs are in consistent order. It is shown that the inference rules of FWFD, which are similar to classical case for Armstrong's Axioms,arc sound and complete. |
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| Keywords: | relation database semantic proximity strong function dependency week function dependency |
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