DBI202 (Full) Question and Answers 2024 | Exam Review

DBI202 (Full) Question and Answers 2024 | Exam
Review
QN=1 (6803) A ____ is a logically coherent collection of data with some inherent
meaning, representing some aspect of real world and being designed, built and
populated with data for a specific purpose
a. Database
b. Database Instance
c. Schema
d. Schema Instance ** Answ** a

QN=2 (6801) Choose the most correct statement.
a. Database is created and maintained by a DMBS
b. All of the others
c. Database is a collection of data that is managed by a DBMS
d. Database is a collection of information that exists over a long period of time **
Answ** b

QN=3 (6802) Which of following is never used as a data model?
a. Hierarchical data model
b. None of the others
c. Graph-based data model
d. Tree-based data model
e. Relational data model ** Answ** b

QN=4 (6817) A ____ is a relation name, together with the attributes of that relation.
a. schema
b. database
c. database instance
d. schema instance ** Answ** a

QN=5 (6824) A ___ is a notation for describing the structure of the data in a database,
along with the constraints on that data
a. data model
b. database management system
c. data operation
d. data manipulation ** Answ** a

QN=6 (6827) A _____ is a language for defining data structures
a. DDL
b. DML
c. DCL
d. None of the others ** Answ** a

QN=7 (6834) Which statement is used to remove a relation named R?

,a. DROP TABLE R;
b. REMOVE TABLE R;
c. DELETE TABLE R;
d. TRUNCATE TABLE R; ** Answ** a

QN=8 (6829) What is another term for a row in a relational table?
a. Attribute
b. Tuple
c. Field
d. Relation ** Answ** b

QN=9 (7961) Given a relation R(A,B,C,D). Which of the followings is trivial?
a. A->AB
b. A->->AB
c. A->BCD
d. A->->BCD ** Answ** d

QN=10 (7972) Let R(ABCD) be a relation with functional dependencies
{A -> B,
C -> B,
B -> D}
What is the key for R (choose one)
a. AB
b. AC
c. AD
d. BD ** Answ** b

QN=11 (7966) Suppose R is a relation with attributes A1, A2, A3, A4.
The only key of R is {A1, A2}. So, how many super-keys do R have?
a. 4
b. 8
c. 12
d. 16 ** Answ** a

QN=12 (7990) 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)?
a. R is in First Normal Form
b. R is in Second Normal Form
c. R is in Third Normal Form
d. R is in Boyce Codd Normal Form ** Answ** a

,QN=13 (7978) The relation R(ABCD) has following FDs:
{ A -> B ; B -> A ; A -> D ; D -> B }
a. R is in 3NF
b. R is not in 3NF
c. R is not in 2NF
d. None of the others ** Answ** a

QN=14 (7976) 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:
a. The FD set of R is not canonical and R is in BCNF
b. The FD set of R is canonical and R is not in BCNF
c. The FD set of R is not canonical and R is not in BCNF ** Answ** a

QN=15 (7999) What is the difference between the 2NF and the 3NF?
a. 2NF deals with partial functional dependency, while 3NF deals with transitive
functional dependency
b. 2NF deals with transitive functional dependency, while 3NF deals with partial
functional dependency ** Answ** a

QN=16 (7993) What is "de-normalization"?
a. De-normalization means allowing redundancy in a table
b. De-normalization means allowing duplicate columns appeared in a table
c. De-normalization means allowing a table to have more than 3 columns
d. De-normalization means allowing a table to have more than 1024 columns **
Answ** a

QN=17 (8004) What is the benefit of "de-normalization"?
a. "de-normalization" has no benefit
b. The main benefit of de-normalization is improved performance with simplified data
retrieval (this is done by reduction in the number of joins needed for data processing)
c. The main benefit of de-normalization is eliminating redundant information from a table
and organizing the data so that future changes to the table are easier ** Answ** b

QN=18 (8022) The key for a weak entity set E is .........
a. Zero or more attributes of E
b. The set of attributes of supporting relationships for E
c. The set of attributes of supporting entity sets
d. Zero or more attributes of E and key attributes from supporting entity sets ** Answ**
d

QN=19 (8019) A class in UML is similar to...........

, a. An entity set in E/R model
b. An attribute in E/R model
c. A Relationship in E/R model
d. None of the others ** Answ** a

QN=20 (8013) A(n) _____ provides a means to analyze business requirements so as to
standardize organizational vocabulary, enforce business rules, and ensure adequate
data quality
a. Entity Relationship Diagram
b. Relation Schema Design
c. All of the others
d. None of the others ** Answ** a

QN=21 (8032) An association class in UML is similar to ______ in the ER model
a. attributes on a relationship
b. Attributes
c. Entities
d. entity sets ** Answ** a

QN=22 (8009) In UML, what is the difference between an aggregation and a
composition?
a. In composition, when the owning object is destroyed, so are the contained objects. In
aggregation, this is not necessarily true.
b. In aggregation, when the owning object is destroyed, so are the contained objects. In
composition, this is not necessarily true.
c. All of the others
d. There is no difference between an aggregation and a composition ** Answ** a

QN=23 (8222) Which of the following is NOT a standard aggregation operator?
a. GROUP
b. SUM
c. COUNT
d. AVG ** Answ** a

QN=24 (8238) Consider the law, that holds for set relations:
T intersect(R union S) = (T intersect R) union (T intersect S)
The above law still hold for bag relations?
a. True
b. False ** Answ** b

QN=25 (8236) Choose the correct statement:
a. Aggregate functions perform a calculation on a set of values and return a single value
b. Aggregate functions perform a calculation on a single value and return a single value
c. Aggregate functions perform a calculation on a set of values and return a relation
d. Aggregate functions perform a calculation on a set of values and return a row **
Answ** a