Database Management Systems Interview Questions/Answers

The database management system is a management system to stores the data for any application. so in the concept of building a dynamic application, we always need for Database, and to manage that we need a database management system.

So it’s a big topic for interviews and has a high chance to be asked in an interview about the DBMS. so here we are including some basic to advanced Database management systems (DBMS) Interview questions and answers so one can prepare for this topic very well and crack the coding interviews or can use them in coding competitions, and university exams.

Which normal form is considered adequate for relational database design?

1. 2 NF
2. 3 NF
3. 4 NF
4. BCNF

Answer – (2) 3 NF

The concept of locking can be used to solve the problem of

lost update
uncommitted dependency
inconsistent data
deadlock

1. 1 and 4
2. 2, 3 and 4
3. 1, 2 and 3
4. All 1, 2, 3, and 4 can be solved

Answer – (3) 1, 2 and 3

If every non-key attribute is functionally dependent on the primary key, then the relationship will be in

1. first normal form
2. second normal form
3. third normal form
4. fourth normal form

Answer – (3) third normal form

The column of a table is referred to as the

1. tuple
2. attribute
3. entity
4. degree

Answer – (2) attribute

Given the functional dependencies

X → W; X → Y; Y → Z and Z → PQ

which of the following does not hold good

1. X → Z
2. W → Z
3. X → WY
4. None of the above

Answer – (2) W → Z

What are the potential problems when a DBMS executes multiple transactions concurrently?

The lost update problem
The dirty read problem
The unrepeatable read problem
The phantom problem

1. 3 and 4 only
2. 1, 2, and 4 only
3. 2 and 3 only
4. All of 1, 2, 3 and 4

Answer – (4) All of 1, 2, 3 and 4

The data flow model of an application mainly shows

1. the underlying data and the relationships among them
2. processing requirements and the flow of data
3. decision and control information
4. communication network structure

Answer – (2) processing requirements and the flow of data

Which of the following desired features are beyond the capability of relational algebra?

1. Aggregate computation
2. Multiplication
3. Finding transitive closure
4. All of the above

Answer – (4) All of the above

In an airline reservation system, the entities are data, flight number, place of departure, destination, type of plane, and seats available. The primary key is

1. fligh number
2. fligh number + place of departure
3. fligh number + date
4. fligh number + destination

Answer – (3) flight number + date

For a database relation R(a,b,c,d) where the domains of a, b, c, and d include only atomic values, only the following functional dependencies and those that can be inferred from their hold.

a → c
b → d
The relation is in

1. first normal form but not in the second normal form
2. second normal form but not in the third normal form
3. third normal form
4. none of the above

Answer – (1) First normal form but not in second normal form

In an E-R diagram, ellipses represent

1. entity sets
2. relationship among entity sets
3. attributes
4. the link between attributes and entity sets

Answer – (3) attributes

The set of permitted values of each attribute is called its

1. attribute set
2. attribute range
3. domain
4. group

Answer – (3) domain

A data model is a collection of conceptual tools for describing

1. data and data relationships
2. data semantics and consistency constraints
3. data, data relationship, data semantics, and consistency constraints
4. none of the above

Answer – (3) data, data relationship, data semantics, and consistency constraints

Choose the incorrect statements

In a network model, data is represented by a collection of records, and relationships among data are represented by links.
In a hierarchical model, data and relationships among data are represented by records and links respectively.
In a hierarchical model, the records are organized as a collection of arbitrary graphs.
In the network model, the records are organized as a collection of trees.

1. 1 and 3 only
2. 2 and 3 only
3. 3 and 4 only
4. All are correct

Answer – (4) All are correct

Choose the correct statements.

1. An alternate key is a candidate key that is not a primary key
2. An alternate key is a primary key that is not a candidate key
3. An alternate key is a candidate key that is also a primary key
4. None of the above

Answer – (1) An alternate key is a candidate key that is not a primary key

The e-R modeling technique is a

1. top-down approach
2. bottom-up approach
3. left-right approach
4. both top-down and bottom-up

Answer – (1) top-down approach

The third normal form is inadequate in situations where the relation

1. has multiple candidate keys
2. has candidate keys that are composite
3. has overlapped candidate keys
4. All of the above

Answer – (4) All of the above

Redundancy is dangerous as it is a potential threat to data

1. integrity
2. consistency
3. sufficiency
4. both (a) and (b) above

Answer – (4) both (a) and (b) above

An attribute of the table matching the primary key of another table is called as

1. foreign key
2. secondary key
3. candidate key
4. composite key

Answer – (1) Foreign key

Choose the correct statement

1. Network models are complicated by physical keys, but the relational model is faster because it uses logical keys.
2. Network models are complicated by logical keys, but the relational model is faster because it uses physical keys.
3. Network models are complicated by logical keys, but the relational model is slower because it uses physical keys.
4. Network models are complicated by physical keys but the relational model is slower because it uses logical keys.

Answer – (1) Network models are complicated by physical keys, but the relational model is faster because it uses logical keys.

Note – More interview questions and answers will be added from time to time.