DBI202 Exam with Correct Detailed Answers 2025.

DBI202 Exam with Correct Detailed Answers 2025
Suppose we have a relation R(ABCD) with FD's: BC -> A ; AD -> C ;
CD -> B ; BD -> C

R is not in BCNF

Let R(A,B,C,D) with the following FDs: {AB->C, AC->B, AD->C}
Choose a correct statement about R

R is in 2NF

Given a R(A,B,C,D) with the following FDs: AB->D BC->A AD->B CD-
>B AD->C Choose a correct statement about R:

The FD set of R is not canonical and R is in BCNF

Consider the following functional dependencies a,b -> c,d e,g,h -
> f,j a,c -> b,d p,q -> r,s e,f,g -> h,i s -> t f,g -> j q -> u
g,h -> i Which of the following best describes the relation
R(e,f,g,h,i,j)?

| R is in First Normal Form

3NF concept is related to (choose 1 answer only):

All of the others

Which of the following relations is in third normal form (3NF)? |
R(ABCD) with FD's: ACD -> B ; AC -> D ; D -> C ; AC -> B

R is in 3NF

The relation R(ABCD) has following FDs: { AB -> C ; ABD -> C ;
ABC -> D ; AC -> D} Choose a correct statement about R?

R is not in 3NF

Which of the following statements is true?

,DBI202 Exam with Correct Detailed Answers 2025
All of the others

Normalization is a process of analyzing the given relation schema
based on their Functional Dependencies (FDs) and primary keys to
achieve the following:

All of the others

How to eliminate anomalies when we design a database?

We should decompose relation to eliminate anomalies

Look at the following statements: (a)All relations in 3NF are
also in 2NF (b)All relations in 2NF are also in 1NF (c)All
relations in 1NF are also in BCNF (d)All relations in 1NF are
also in 3NF

(a) and (b) are true

Which of the following are guidelines for designing the
relational schema ?

| All of the others

Regardless of whatever any other transaction is doing, a
transaction must be able to continue with the exact same data set
it started with. The above describes which property of a
transaction?

Isolation

Pay attention into the following query: SELECT * FROM R WHERE A
LIKE '%a%'; So, in the above case, the wildcard % represents
what?

% (percent sign) represents zero, one, or more character

, DBI202 Exam with Correct Detailed Answers 2025
What does the keyword ESCAPE mean?

The keyword ESCAPE is used to match any string that contains the
characters "%" or "_"

The SQL BETWEEN operator:

| Specifies a range to test

Foreign key constraints are created by using "_____" keyword to
refer to the primary key of another table

REFERENCES

What is difference between PRIMARY KEY and UNIQUE KEY ?

A table can have more than one UNIQUE KEY--- one PRIMARY KEY

To drop a DEFAULT constraint, use the following SQL:

| ALTER TABLE Persons ALTER COLUMN City DROP DEFAULT

Choose the most correct statement about PRIMARY KEY:

All of the others

Three basic types of database integrity constraints are:
(a)Entity integrity (b) Domain integrity (c) Referential
integrity (d) Primary key integrity

(a) and (b) and (c) are true

Well-designed ____ can reduce disk I/O operations and consume
fewer system resources therefore improving query performance

Indexes

Which of the following statements is the most correct?