DBMS Basics - Technical Questions and Answers

DBMS - Database Management System
DBMS - Basics

41.	What is normalization?
	Answer: It is a process of analysing the given relation schemas based on their Functional Dependencies (FDs) and primary key to achieve the properties (1).Minimizing redundancy, (2). Minimizing insertion, deletion and update anomalies. Workspace Report errors ... Name : Email: View Answer

42.

What is Functional Dependency?

43.	What is Lossless join property?
	Answer: It guarantees that the spurious tuple generation does not occur with respect to relation schemas after decomposition. Workspace Report errors ... Name : Email: View Answer

44.	What is 1 NF (Normal Form)?
	Answer: The domain of attribute must include only atomic (simple, indivisible) values. Workspace Report errors ... Name : Email: View Answer

45.	What is Fully Functional dependency?
	Answer: It is based on concept of full functional dependency. A functional dependency X Y is full functional dependency if removal of any attribute A from X means that the dependency does not hold any more. Workspace Report errors ... Name : Email: View Answer

46.	What is 2NF?
	Answer: A relation schema R is in 2NF if it is in 1NF and every non-prime attribute A in R is fully functionally dependent on primary key. Workspace Report errors ... Name : Email: View Answer

47.	What is 3NF?
	Answer: A relation schema R is in 3NF if it is in 2NF and for every FD X A either of the following is true X is a Super-key of R. A is a prime attribute of R. In other words, if every non prime attribute is non-transitively dependent on primary key. Workspace Report errors ... Name : Email: View Answer

48.	What is BCNF (Boyce-Codd Normal Form)?
	Answer: A relation schema R is in BCNF if it is in 3NF and satisfies an additional constraint that for every FD X A, X must be a candidate key. Workspace Report errors ... Name : Email: View Answer

49.	What is 4NF?
	Answer: A relation schema R is said to be in 4NF if for every Multivalued dependency X Y that holds over R, one of following is true. 1.) X is subset or equal to (or) XY = R. 2.) X is a super key. Workspace Report errors ... Name : Email: View Answer

50.	What is 5NF?
	Answer: A Relation schema R is said to be 5NF if for every join dependency {R1, R2, ..., Rn} that holds R, one the following is true 1.) Ri = R for some i. 2.) The join dependency is implied by the set of FD, over R in which the left side is key of R. Workspace Report errors ... Name : Email: View Answer