Managing merged data by vague functional dependencies

In this paper, we propose a new similarity measure between vague sets and apply vague logic in a relational database environment with the objective of capturing the vagueness of the data. By introducing a new vague Similar Equality (S-EQ) for comparing data values, we first generalize the classical Functional Dependencies (FDs) into Vague Functional Dependencies (VFDs). We then present a set of sound and complete inference rules. Finally, we study the validation process of VFDs by examining the satisfaction degree of VFDs, and the merge-union and merge-intersection on vague relations.