MINIMAL COVER OF FUNCTIONAL DEPENDENCIES
A minimal cover of a set of FDs F is a minimal set of functional dependencies F min that is equivalent to F. There can be many such minimal covers for a set of functional dependencies F. Steps to derive minimal cover for a FD set . 1)Right Hand Side (RHS) of all FDs should be single attribute . 2)Eliminate redundant functional dependencies if any . Given relation R(A,B,C) and FDs : { AB -> C, C -> A } FDmin ={AB à C} ,here C-->A is redundant dependency 3)Remove redundant attribute on LHS if any . Consider FD , AB -> C If AB+ = A+ we can say B is redundant then reduce to A à C If AB+ =B+ we can say A is redundant then reduce to B à C