Abstract: The accurate and approximate measures of rough functional dependency are proposed in this paper in order to find potential and interesting patterns for rough relational database.The approximate measure of functional dependency for classical relational database and its properties are reviewed，then the accurate and approximate measure of rough functional dependency are introduced，moreover their formalization definitions are given，as well as the basic property with which accurate and approximate measure satisfied are investigated，and the example for related formulae are given.The introduction of approximate theory of rough functional dependency will accelerate the development of knowledge discovery for rough relational database and extend its research field.

Key words: Rough Relational Database（RRDB）, approximate measure, accurate measure

摘要： 为了发现粗糙关系数据库中潜在的和有趣的模式，提出并研究了粗糙函数依赖的近似度量和精确度量。首先，对于关系数据库的近似度量及其满足的性质进行了研究，在此基础上提出了粗糙关系数据库（Rough Relational Database，简称RRDB）的近似度量及精确度量，对该两种度量进行了形式化定义，并且进一步研究了他所满足的性质，给出了相应的实例。该度量的提出及其性质的研究有利于粗糙关系数据库的知识发现及数据查询的研究，并且进一步扩大了粗糙关系数据库的研究领域。

关键词: 粗糙关系数据库（RRDB）, 近似度量, 精确度量