摘要
数据库设计的目标是生成一组模式,使数据存储既减少冗余,又可方便地获取信息。这是通过设计满足适当范式的模式来实现的。函数依赖FD是有效的工具。对于多粒度模糊时态数据库设计来说,模糊值和多粒度模糊时态序列的映射关系是将传统FD扩展到模糊时态函数依赖FTFD的关键,通过分析属性集的有限闭包、时态类型集的封闭集、属性集在给定时态上的依赖等概念,得到模糊/时态向量的特征描述,并对此方法的正确性进行了论证。此方法能方便地在计算机上表达模糊属性值和模糊时态序列的映射关系,为模糊时态数据库范式的判定和分解算法提供有效的手段。
The goal of database design is to generate a set of patterns,which not only reduces data storage redundancy,but also conveniently accesses to information.This is by design to meet the appropriate normal form model achieved.Functional dependency FD is an effective tool.The key is the mapping of fuzzy-valued and multi-granularity fuzzy temporal sequence to extend the traditional FD to fuzzy temporal functional dependency FTFD for multi-granularity fuzzy temporal database design.To effectively express fuzzy/temporal characteristic of vector space on fuzzy temporal database design by analyzing limited closure of attribute set,the closed set of temporal types set,the concepts of attribute set in a gaven temporal depends on the state of such as the fuzzy/temporal characterization vector.And the correctness of this method was demonstrated.This method can be easily expressed on the computer,to determine mapping relations of fuzzy attribute values and fuzzy temporal sequence for the paradigm of fuzzy temporal database and to provide an effective means of decomposition.
出处
《计算机科学》
CSCD
北大核心
2011年第6期211-216,共6页
Computer Science
基金
国家自然科学基金(60873010)资助
关键词
模糊时态数据库
函数依赖
时间粒度
有限闭包
FTFD
Fuzzy temporal databases
Functional dependency
Time granularity
Limited closure
FTFD
