If a relation is in BCNF, then it is also in
| A. | 1 NF |
| B. | 2 NF |
| C. | 3 NF |
| D. | All of the above |
|
Option: D Explanation : Click on Discuss to view users comments. Mithinga Kumar Boro said: (4:59am on Tuesday 10th April 2018)
i want to know why its answer is all of the above.
|
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 |
|
Option: D Explanation : Click on Discuss to view users comments. 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.
|
Consider the following
S1: Foreign key allows null values.
S2: Every binary tables is in BCNF
Which of the following is true
| A. | Both S1 and S2 are true |
| B. | S1 is true |
| C. | S2 is true |
| D. | None of these |
|
Option: B Explanation : Click on Discuss to view users comments. |
Consider the following functional dependencies in a database:
Date_of_Birth —> Age Age —> Eligibility
Name —> Roll_number Roll_number -> Name
Course_number ---> Course—> name Course_number —> Instructor
(Roll number; Course_number) —> Grade
The relation (Roll_number; Name; Date_of birth, Age) is
| A. | in second normal form but not in third normal form |
| B. | in third normal form but not in BCNF |
| C. | in BCNF |
| D. | in none of the above |
|
Option: D Explanation : Click on Discuss to view users comments. |
The relation scheme student performance (name, courseNo, rollNo, grade) has the following functional dependencies:
name, curseNo --> grade
Rol INo, courseNo —> grade
name —> rollNo
rollNo —> name
The highest normal form ofthis relation scheme is:
| A. | 2 NF |
| B. | 3 NF |
| C. | BCNF |
| D. | 4 NF |
|
Option: B Explanation : Click on Discuss to view users comments. Soniya said: (12:29am on Sunday 18th June 2017)
It's not even in 2NF
|
