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dbi-202 Exam Study Questions and Answers
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dbi-202 Exam Study Questions and Answers Suppose we have a relation R(ABCD) with FD's: BC -> A ; AD -> C ; CD -> B ; BD -> C - Answer- 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 - Answer-R is in 2NF Giv...

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EMILLECT 2024/2025 ACADEMIC YEAR ©2024 EMILLECT. ALL RIGHTS RESERVED FIRST PUBLISH OCTOBER, 2024




dbi-202 Exam Study Questions and
Answers

Suppose we have a relation R(ABCD) with FD's: BC -> A ; AD -> C ; CD -> B ; BD -> C - Answer✔✔-

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 - Answer✔✔-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: - Answer✔✔-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)? -

Answer✔✔-| R is in First Normal Form


3NF concept is related to (choose 1 answer only): - Answer✔✔-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 - Answer✔✔-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? - Answer✔✔-R is not in 3NF


Which of the following statements is true? - Answer✔✔-All of the others

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,EMILLECT 2024/2025 ACADEMIC YEAR ©2024 EMILLECT. ALL RIGHTS RESERVED FIRST PUBLISH OCTOBER, 2024


Normalization is a process of analyzing the given relation schema based on their Functional

Dependencies (FDs) and primary keys to achieve the following: - Answer✔✔-All of the others


How to eliminate anomalies when we design a database? - Answer✔✔-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 -

Answer✔✔-(a) and (b) are true


Which of the following are guidelines for designing the relational schema ? - Answer✔✔-| 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? - Answer✔✔-Isolation


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

case, the wildcard % represents what? - Answer✔✔-% (percent sign) represents zero, one, or

more character


What does the keyword ESCAPE mean? - Answer✔✔-The keyword ESCAPE is used to match any

string that contains the characters "%" or "_"


The SQL BETWEEN operator: - Answer✔✔-| Specifies a range to test




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, EMILLECT 2024/2025 ACADEMIC YEAR ©2024 EMILLECT. ALL RIGHTS RESERVED FIRST PUBLISH OCTOBER, 2024


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

another table - Answer✔✔-REFERENCES


What is difference between PRIMARY KEY and UNIQUE KEY ? - Answer✔✔-A table can have

more than one UNIQUE KEY--- one PRIMARY KEY


To drop a DEFAULT constraint, use the following SQL: - Answer✔✔-| ALTER TABLE Persons ALTER

COLUMN City DROP DEFAULT


Choose the most correct statement about PRIMARY KEY: - Answer✔✔-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 - Answer✔✔-(a) and (b) and (c) are true


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

therefore improving query performance - Answer✔✔-Indexes


Which of the following statements is the most correct? - Answer✔✔-| All of the others


What is a view? - Answer✔✔-A view is a virtual table which results of executing a pre-compiled

query. A view is not a part of the physical database schema, while the regular tables are.


What structure can you implement for the database to speed up table reads? - Answer✔✔-

indexes


What are the drawbacks of indexes? (a)Indexes require more disk space (b) Indexes make

UPDATE, INSERT, DELETE statement slower (c)Indexes have no any drawback (d) Indexes make

SELECT statement slower - Answer✔✔-(a) and (b) are true

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