Partial dependency

A functional dependency that holds in a relation is partial when removing one of the determining attributes gives a functional dependency that holds in the relation.Eg if {A,B} → {C} but also {A} → {C} then {C} is partially functionally Read More …

Inference Rules

Rules of Inference for functional dependencies, called inference axioms or Armstrong axioms, after their developer, can be used to find all the FDs logically implied by a set of FDs. These rules are sound , meaningthat they are an immediate Read More …