Database Questions QUESTION 8 IfA B and B A are existing f

Database Questions:

QUESTION 8 IfA --> B and B --> A are existing functional dependencies, which of the following are NOT equivalent functional dependencies? A - >B and B> A A - > B, X and B - -> A, X X--> A and A--> B O X, A -> B, x and X, B - > A, X QUESTION 9 ENROLLMENT Observe the table ENROLLMENT ENROLLMENT StudentD StudentName ClassID ClassName oe Bob Lisa E1 E1 H1 Engishl Engshl Historyi This table will be used for the following questions citing table ENROLLMENT Which of the following functional dependencies does NOT exist in the table ENROLLMENT? O StudentID > StudentName StudentName --> StudentID StudentID--> ClassID O ClassID > ClassName

Solution

Answer of Question 8:

if A -->B and B-->A are existing functional dependencies which of the following are not equivalent functional dependencies then the X-->A and A-->B is not equivalent functional dependency i.e. the option 3 is correct answer because here existing functional dependency is between only A and B not X so here X-->A is wrong .

So Answer is option 3 i.e X-->A and A-->B

Answer of Question 9:

Here the fuctional dependency which not exist in table is ClassID-->ClassName here ClassID has functional dependency on StudentID.

So answer is ClassID-->ClassName.

Answer of Question 10:

A trivial functional dependencies are said to be trivial because they are satisfied by all relations. Suppose functional dependency of the form A–>B is trivial if  . or we can say that a trivial Functional Dependency is the one where RHS is a subset of LHS.

Here partial functional dependency is not exit in FLIGHT table so answer is partial i.e. option 3.