A Fuzzy Temporal Model and Query Language for FTER Databases
Liguo Deng, Zhiheng Liang, Yong Zhang · 2008
In this paper, we propose a temporal extension to an extended ERT model and extend database temporal models to handle the fuzzy numbers. The concept of lifespan for entities and relationships is incorporated in the FTER model. We specify a fuzzy temporal query and update temporal language which is an extension from the TQuel language. The concepts of fuzzy temporal expressions, fuzzy temporal selection, fuzzy temporal join and fuzzy temporal projection are introduced, and their use in the query language is illustrated. We also discuss reducibility of the semantics to the language when applied to a static database and define the semantics of update operations.