DBI201 EXAM TEST BANK
QUESTIONS AND
ANSWERS ALL CORRECT
What is a graph database? - Answer ✔ A graph database is a database that uses graph
structures with nodes, edges and properties to represent and store information
A ____ is a powerful tool for creating and managing large amounts of data efficiently
and allowing it to persist over long periods of time, safely - Answer ✔ DBMS
A ______ is a collection of programs that enables user to create and maintain
databases. In other words, it is general-purpose software that provides the users with
the processes of defining, constructing and manipulating the databases for various
applications - Answer ✔ DBMS
Today, the two important data models are: - Answer ✔ The relational data model
(including object-relational extensions) and the semi-structured data model (including
XML and related standards)
Today, in a modern DBMS, the queries are parsed and optimized by - Answer ✔ query
compiler
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 - Answer ✔ Database
What is the hierarchical data model? - Answer ✔ A hierarchical data model is a data
model in which the data is organized into a tree-like structure
A person who is responsible for the structure or schema of the database is called: -
Answer ✔ a database administrator
A database administrator (DBA) is a person that is also known by the title: - Answer ✔
Database Coordinator or Database Programmer
A ___ is a notation for describing the structure of the data in a database, along with the
constraints on that data - Answer ✔ data model
,Data Definition language (DDL) is used to ...... - Answer ✔ declare database schemas
Which is the subset of SQL commands used to manipulate Database structures,
including tables? - Answer ✔ DDL (Data Definition Language)
Which of the followings is part of data model? - Answer ✔ All of the others
"R(A,B,C,D)" is an example of: - Answer ✔ A schema
Which statement is used to remove a column named D from the relation R? - Answer ✔
ALTER TABLE R DROP COLUMN D;
What is a primary key? - Answer ✔
a. A primary key is the field(s) in a table that uniquely defines that table in a database -
Answer ✔ A primary key is the field(s) in a table that uniquely defines the row in the
table
A ____ is a relation name, together with the attributes of that relation. - Answer ✔
schema
Which statement is used to add a column named D into the relation R? - Answer ✔
ALTER TABLE R ADD D [DataType];
Which one of the following is NOT a DML command? - Answer ✔ GRANT
What is another term for a row in a relational table? - Answer ✔ Tuple
The relational operator that adds all possible pairs of rows from two tables is known as
the .... - Answer ✔ product
What is a functional dependency? - Answer ✔ A functional dependency (A->B) occurs
when the attribute A uniquely determines B
Consider a relation with schema R(A, B, C, D) and FD's BC -> D, D -> A, A -> B. Which
of the following is the key of R? - Answer ✔ BC
Given the relation schema R(A,B,C) and functional dependencies F = {AB-> C, B->A, C-
>B}. Which attribute(s) is/are prime? - Answer ✔ B and C
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
3NFconcept is related to (choose 1 answer only): - Answer ✔ All of the others
Which of the following relations is in third normal form (3NF)? - Answer ✔ 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? - Answer ✔ R is not in 3NF
Which of the following statements is true? - Answer ✔ 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: - 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.
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
Often, a DBMS allows us to build a single index on ____ attribute(s) (choose the most
correct answer) - Answer ✔ only one
Suppose an updatable view ParamountMovies is associated with Movies relation.
Choose a correct answer. - Answer ✔ An update on ParamountMovies is translated into
Movies
