Q25,paper3,j14. Consider the schema R = {S, T, U, V} and the dependencies S →T, T →U, U→V and V →S If R = (R1and R2) be a decomposition such that R1∩R2= φ then the decomposition is

(A) not in 2NF

(B) in 2NF but not in 3NF

(C) in 3NF but not in 2NF

(D) in both 2NF and 3NF .

 

Answer D.

Explanation.

Let the R1={S,T}

R2={u,v}

S-> T. all the non key are fully functional dependent on key . hence R1 is in 2nf. Not transitive dependency hence 3nf.

Similarly R2.