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Exercise : Database Management System MCQ Questions and Answers

Question 1

Which level of Abstraction describes how data are stored in the data base ?

A.  
B.  
C.  
D.  

Correct Answer : C. Physical level

Description :
Physical Level is The lowest level of abstraction describes how the data are actually stored. The physical level describes complex low-level data structures in detail.

Question 2

Student(ID, name, dept name, tot_cred) In this query which attribute form the primary key?

A.  
B.  
C.  
D.  

Correct Answer : D. ID

Description :
ID The attributes name ,dept and tot_cred can have same values unlike ID .

Question 3

Views are useful for _____ unwanted information, and for collecting together information from more than one relation into a single view.

A.  
B.  
C.  
D.  

Correct Answer : C. Hiding

Description :
This is Primary Advantage of Views in Database
Views can represent a subset of the data contained in a table; consequently, a view can limit the degree of exposure of the underlying tables to the outer world: a given user may have permission to query the view, while denied access to the rest of the base table.
Views can join and simplify multiple tables into a single virtual table
Views can act as aggregated tables, where the database engine aggregates data (sum, average etc.) and presents the calculated results as part of the data
Views can hide the complexity of data; for example a view could appear as Sales2000 or Sales2001, transparently partitioning the actual underlying table

Question 4

In _______________ index instead of storing all the columns for a record together, each column is stored separately with all other rows in an index.

A.  
B.  
C.  
D.  

Correct Answer : B. Column store

Description :
A database index is a data structure that improves the speed of data retrieval operations on a database table at the cost of additional writes.

Question 5

The relation “divides” on a set of positive integers is ________.

A.  
B.  
C.  
D.  

Correct Answer : A. Anti symmetric and transitive

Description :
No answer description available for this question. Let us discuss.

Question 6

To include integrity constraint in a existing relation use :

A.  
B.  
C.  
D.  

Correct Answer : C. Alter table

Description :
Alter table
SYNTAX – alter table table-name add constraint , where constraint can be any constraint on the relation.

Question 7

Which of the following is true ?

A.  
B.  
C.  
D.  

Correct Answer : A. A relation in BCNF is always in 3NF

Description :
Since BCNF is higher form of 3NF, so a relation in BCNF must be in 3NF but the reverse is not true

Question 8

Create table employee (name var char ,id integer) What type of statement is this ?

A.  
B.  
C.  
D.  

Correct Answer : D. DDL

Description :
DDL
Data Definition language is the language which performs all the operation in defining structure of relation.

Question 9

Find Incorrect match?

A.  
B.  
C.  
D.  

Correct Answer : B. Rectangle - DAL

Description :
Rectangle - The E-R Model

Question 10

Which of the following is used to store movie and image files ?

A.  
B.  
C.  
D.  

Correct Answer : C. Blob

Description :
SQL therefore provides large-object data types for character data (clob) and binary data (blob). The letters “lob” in these data types stand for “Large OBject.”

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