# Relational Database Interview Preparation Guide **Download PDF** Add New Question

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Relational Frequently Asked Questions in various Relational Database Interviews asked by the interviewer. So learn Relational with the help of this Relational Database Interview questions and answers guide and feel free to comment as your suggestions, questions and answers on any Relational Database Interview Question or answer by the comment feature available on the page.

## 16 Relational Database Questions and Answers:

### 1 :: Explain 2NF?

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.

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### 2 :: Explain 3NF?

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.

► 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.

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### 3 :: Explain 4NF?

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

► X is subset or equal to (or) XY = R.

► X is a super key.

► X is subset or equal to (or) XY = R.

► X is a super key.

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### 4 :: Explain DML Compiler?

It translates DML statements in a query language into low-level instruction that the query evaluation engine can understand.

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### 5 :: Explain 5NF?

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

► Ri = R for some i.

► The join dependency is implied by the set of FD, over R in which the left side is key of R.

► Ri = R for some i.

► The join dependency is implied by the set of FD, over R in which the left side is key of R.

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### 6 :: Explain DDL Interpreter?

It interprets DDL statements and record them in tables containing metadata.

Its a language in database through which you can make the logical design of the schemas ....

Its a language in database through which you can make the logical design of the schemas ....

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### 7 :: Explain degree of a Relation?

Degree of a Relation is the number of attribute of its relation schema.

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### 8 :: Explain Fully Functional dependency?

Fully Functional dependency 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.

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### 9 :: Explain the different types of JOIN operations?

Equi Join:

This is the most common type of join which involves only equality comparisons. The disadvantage in this type of join is that there

This is the most common type of join which involves only equality comparisons. The disadvantage in this type of join is that there

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### 10 :: Explain Relational Algebra?

It is procedural query language. It consists of a set of operations that take one or two relations as input and produce a new relation.

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