DBMS - MVD & 4NF

Consider a relation R(A,B,C) with multivalued dependency A ↠ B.

Suppose there at least 3 different values for A, and each value of A is associated with at least 4 different B values and at least 5 different C values. What is the minimum number of tuples in R?

• 60

• 15

• 12

• 27

For the relation

Apply(SSN,cName,date,major)

with functional dependency

SSN,cName → date,

what real-world constraint is captured by

SSN ↠ cName,date?

• A student can only apply to one major at each college.

• A student can apply to different majors at each college, but each major must be applied for on a different date.

• A student must apply to the same set of majors at all colleges.

• A student must apply to a different major at each college.

Consider relation StudentInfo(sID, name, dorm, major) with functional dependency sID → name and multivalued dependency sID ↠ dorm. What schema would be produced by the 4NF decomposition algorithm?

• StudentInfo(sID, name, dorm, major)

• S1(sID,name), S2(sID,dorm,major)

• S1(sID,name,dorm), S2(sID,major)

• S1(sID,name), S2(sID,dorm), S3(sID,major)

Here above is an instance of a relation R(A,B,C)

Which of the following multivalued dependencies does this instance of R not satisfy?

• AB ↠ C

• A ↠ B

• BC ↠ C

• C ↠ B

Here is an instance of a relation R(A,B,C,D):

Which of the following multivalued dependencies does this instance of R satisfy?

• BD ↠ C

• B ↠ CD

• D ↠ AB

• AB ↠ C

Consider relation R(A,B,C,D,E) with multivalued dependencies:

A ↠ B, B ↠ D

Suppose R contains the tuples (0,1,2,3,4) and (0,5,6,7,8). Which of the following tuples must also be in R?

• (0,1,6,3,4)

• (0,5,2,3,8)

• (0,5,6,3,8)

• (0,1,2,3,8)