Find the candidate key(s) of the relation R(UVWXYZ) with FD set F = {UV → W,…
2015
Find the candidate key(s) of the relation R(UVWXYZ) with FD set
F = {UV → W, XW → Y, U → XZ, Y → U}
- A.
XW
- B.
UV, YV and WXV
- C.
YUV, XV and WV
- D.
None of these
Attempted by 153 students.
Show answer & explanation
Correct answer: B
To find the candidate keys, first identify attributes that do not appear on the right-hand side of any functional dependency. Here, V is the only such attribute, so every candidate key must include V. Next, compute closures for combinations involving V to see which determine all attributes {U,V,W,X,Y,Z}. The closure of UV includes U, V, and via dependencies yields all attributes. Similarly, YV determines U (via Y→U), which leads to all attributes. WXV also determines all attributes through the given dependencies. Thus, the candidate keys are UV, YV, and WXV.
A video solution is available for this question — log in and enroll to watch it.