Database-Management-System
August 29, 2024Database-Management-System
August 29, 2024Functional-Dependency
|
Question 38
|
Which of the statements are true about functional dependency X→ Y in relation R?
a.Whenever two tuples t1 and t2 in R have t1(X)=t2(X) then t1(Y)=t2(Y)
b.Whenever two tuples t1 and t2 in R have t1(Y)=t2(Y) then t1(X)=t2(X)
a.Whenever two tuples t1 and t2 in R have t1(X)=t2(X) then t1(Y)=t2(Y)
b.Whenever two tuples t1 and t2 in R have t1(Y)=t2(Y) then t1(X)=t2(X)
|
a and b
|
|
|
Only a
|
|
|
Only b
|
|
|
Neither a nor b
|
Question 38 Explanation:
→Functional dependency is a relationship that exists when one attribute uniquely determines another attribute.
→If R is a relation with attributes X and Y, a functional dependency between the attributes is represented as X→Y, which specifies Y is functionally dependent on X. Here X is a determinant set and Y is a dependent attribute. Each value of X is associated with precisely one Y value.
→If R is a relation with attributes X and Y, a functional dependency between the attributes is represented as X→Y, which specifies Y is functionally dependent on X. Here X is a determinant set and Y is a dependent attribute. Each value of X is associated with precisely one Y value.
Correct Answer: B
Question 38 Explanation:
→Functional dependency is a relationship that exists when one attribute uniquely determines another attribute.
→If R is a relation with attributes X and Y, a functional dependency between the attributes is represented as X→Y, which specifies Y is functionally dependent on X. Here X is a determinant set and Y is a dependent attribute. Each value of X is associated with precisely one Y value.
→If R is a relation with attributes X and Y, a functional dependency between the attributes is represented as X→Y, which specifies Y is functionally dependent on X. Here X is a determinant set and Y is a dependent attribute. Each value of X is associated with precisely one Y value.
Subscribe
Login
0 Comments