Consider the relation given below and ind the maximum normal form applicable to them
1. R(A, B) with productions { A --> B }
2. R(A, B) with productions { B --> A }
3 R(A, B) with productions {A —> B, B --> A }
4 R(A, B, C) with productions {A -->B, B --> A, AB --> C }
| A. | 1, 2 and 3 are in 3NF and 4 is in BCNF |
| B. | 1 and 2 are in BCNF and 3 and 4 are in 3NF |
| C. | All are in 3NF |
| D. | All are in BCNF |
Answer : D Explanation : Naeem Ahmad said: (12:45am on Wednesday 17th June 2015)
Answer should be A because 4 is not in BCNF.In 4, FDs A-->B and B-->A do not hold property of neither trivial nor super key.A and B are not super key since AB is primary key.FDs are nontrivial FDs.
naresh said: (1:14pm on Friday 4th September 2015)
if single relation is there then it will be in bcnf so a and b are in bcnf but c and d are in 3nf becoz determinant is not always key or super key. so answer should be b.
Prashant said: (2:57am on Friday 1st September 2017)
4 will be in bcnf because the closure of a,b and ab will be {a,b,c} and all will become a key.
|
|
|
Option: A Explanation : Explanation will come here. Explanation will come here. Explanation will come here. Explanation will come here. Explanation will come here. |
