Ace book

Question

Answer 1

FD {X-->YZ, Y-->XZ,Z-->X}

Number of minimal covers and canonical covers both are same.

1. Distribute the right hand side attribute.

    X->Y,X->Z,Y->X,Y->Z,Z->X

2. Remove all the redundancy in left side of the FD's, if it exists.

3. Remove the redundant FD's

    Let say If we remove X->Z and if we get X->Z from other exist FD's then we redundant FD's is removed.

So below these 2 Minimal / Canonical Cover exist.

    1. X->Y,Y->Z,Z->X

    2. X->Y,Y->X,Z->X,X->Z