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 dependent on {A,B}.
A functional dependency X → Y is a partial dependency if some attribute A ε X can be removed from X and the dependency still holds; that is, for some A ε X, (X – {A}) → Y.

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