31.  Which of the following is used to express database consistency? 
Answer: (d).All of the mentioned

32.  Which of the following is not a condition for the third normal form in the case of X→Y? 
Answer: (d).Each attribute in XY is a candidate key for R

33.  F+ is called as the ________ of F 
Answer: (a).Closure

34.  State true or false: A functional dependency must first satisfy the second normal form to satisfy the third normal form. 
Answer: (a).True

35.  State true or false: The fourth normal form does not exist and it is instead called as the BCNF. 
Answer: (b).False

36.  A functional dependency f on R is _______ by a set of functional dependencies F on r if every instance of r(R) that satisfies f also satisfies F. 
Answer: (c).Logically implied

37.  If F is a set of functional dependencies, then the closure of F is denoted by? 
Answer: (c).F+

38.  If a functional dependency is reflexive, B is a subset of A and A is the set of attributes, then 
Answer: (b).A→B holds

39.  State true or false: Armstrong’s axioms allow us to generate all F+ for any given F 
Answer: (a).True

40.  Armstrong axioms are called sound because? 
Answer: (d).They cannot generate incorrect functional dependencies
