A Uniform Framework for Temporal Functional Dependencies with Multiple Granularities

Temporal functional dependencies (TFDs) add a temporal component to clas-sical functional dependencies to deal with temporal data. As an example, whilefunctional dependencies model constraints like “employees with the same role getthe same salary”, TFDs can represent constraints like “for any given month, em-ployees with the same role have the same salary, but their salary may changefrom one month to the next one” or “current salaries of employees uniquely de-pend on their current and previous roles”. In this paper, we propose a generalframework for specifying TFDs, possibly involving different time granularities,and for checking whether or not a given database instance satisfies them. Theproposed framework subsumes existing formalisms for TFDs and it allows one toencode TFDs which are not captured by them.