Functional Dependencies in Vague Relational Databases
Faxin Zhao, Zongmin Ma · 2006
In order to model the real world with imprecise and uncertain information, various extended relational data models were proposed. Vague set, as a generalized fuzzy set, has more powerful ability to process fuzzy information than fuzzy set. In this paper, we propose a kind of vague relational model and a new similarity measure between vague sets based on the set-theoretic approach. Based on the proposed similarity measure, the paper focuses on the issues of vague functional dependencies (VFDs), and then proposes a set of sound inference rules, which are similar to Armstrong's axioms for classical case, for vague functional dependencies. Finally, the paper presents the satisfaction degree of the VFDs and the formula to determine the satisfaction degree of VFDs.