关键词: 模糊时态数据库，函数依赖，时间粒度，有限闭包，FTFD

Abstract: 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八emporal 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八emporal 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.

Key words: Fuzzy temporal databases, Functional dependency, Time granularity, Limited closure, FTFD