Abstract: Conditional Functional Dependencies（CFDs） are extension of Functional Dependencies（FDs） by importing semantic constraints. They can be made extensive use of data inconsistency repair and data cleaning. This paper discusses the semantic rules of CFDs, and mainly studies data inconsistencies detection based on CFDs. Particularly, it introduces confidence coefficients for improving detection rules, which have more advantages on the simplicity and the accurate standardization.

Key words: conditional functional dependencies, functional dependencies, Structured Query Language（SQL）

摘要： 条件函数依赖是函数依赖在语义上的扩充，可以应用于数据清洗工作，在数据库一致性的修复上应用广泛。讨论了条件函数依赖的相关语义规则，重点研究了基于条件函数依赖对违反数据库一致性元组的检测工作，并引入置信度评价机制，对相关的检测规则进行了改进。改进后的检测方法在基于多个函数依赖的检测中显示出了优越性，使得检测工作更为精简，检测标准更加明确。

关键词: 条件函数依赖, 函数依赖, 结构化查询语言（SQL）