CBSE Class 12
Computer Science
08 Database Concepts
30
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Q-1
Consider the following table STUDENT(Roll, Name, Class). Which attribute can uniquely identify a record?
Easy
Keys in a Relational Database
Sample Data
| Roll | Name | Class |
|---|---|---|
| 1 | Amit | XII |
| 2 | Neha | XII |
| 3 | Ravi | XI |
A
Roll
B
Name
C
Class
D
None
Answer: Roll
Explanation: Roll uniquely identifies each record, so it is a primary key.
Q-2
Which of the following is a limitation of traditional file systems?
Easy
File System
A
Better security
B
Data redundancy
C
Faster processing
D
Data integrity
Answer: Data redundancy
Explanation: File systems often suffer from data redundancy.
Q-3
What will be the number of tuples in the table?
Easy
Relational Data Model
Sample Data
| ID | Name |
|---|---|
| 1 | A |
| 2 | B |
| 3 | C |
A
2
B
1
C
3
D
4
Answer: 3
Explanation: There are 3 rows (tuples) in the table.
Q-4
Which of the following best defines a DBMS?
Easy
Database Management System
A
A programming language
B
A collection of files
C
A spreadsheet
D
A software to manage databases
Answer: A software to manage databases
Explanation: DBMS is software used to manage databases efficiently.
Q-5
Which key is used to uniquely identify a record in a table?
Easy
Keys in a Relational Database
A
Primary Key
B
Foreign Key
C
Composite Key
D
Candidate Key
Answer: Primary Key
Explanation: Primary key uniquely identifies each record.
Q-6
Which term refers to a column in a relational table?
Easy
Relational Data Model
A
Tuple
B
Attribute
C
Relation
D
Record
Answer: Attribute
Explanation: Columns are called attributes.
Q-7
What will be the number of attributes in the table?
Easy
Relational Data Model
Sample Data
| ID | Name | Marks |
|---|
A
2
B
1
C
3
D
4
Answer: 3
Explanation: There are 3 columns (attributes).
Q-8
Which key is used to link two tables?
Easy
Keys in a Relational Database
A
Primary Key
B
Candidate Key
C
Composite Key
D
Foreign Key
Answer: Foreign Key
Explanation: Foreign key links tables.
Q-9
Which of the following is an advantage of DBMS over file system?
Easy
Database Management System
A
Reduced redundancy
B
More duplication
C
Less security
D
Manual access
Answer: Reduced redundancy
Explanation: DBMS reduces redundancy.
Q-10
Which type of key is made up of more than one attribute?
Medium
Keys in a Relational Database
A
Primary Key
B
Composite Key
C
Foreign Key
D
Super Key
Answer: Composite Key
Explanation: Composite key consists of multiple attributes.
Q-11
How many records are present?
Easy
Relational Data Model
Sample Data
| ID | Name |
|---|---|
| 1 | A |
| 2 | B |
A
1
B
3
C
2
D
4
Answer: 2
Explanation: There are 2 rows.
Q-12
Which key can uniquely identify a record and can also be chosen as primary key?
Medium
Keys in a Relational Database
A
Foreign Key
B
Composite Key
C
Super Key
D
Candidate Key
Answer: Candidate Key
Explanation: Candidate keys are potential primary keys.
Q-13
Which model organizes data into tables?
Easy
Relational Data Model
A
Relational Model
B
Hierarchical Model
C
Network Model
D
Object Model
Answer: Relational Model
Explanation: Relational model uses tables.
Q-14
Which system stores data in separate files without relations?
Easy
File System
A
DBMS
B
File System
C
RDBMS
D
Cloud System
Answer: File System
Explanation: File system stores data in independent files.
Q-15
Which of the following is NOT a DBMS?
Medium
Database Management System
A
MySQL
B
Oracle
C
MS Excel
D
PostgreSQL
Answer: MS Excel
Explanation: Excel is not a DBMS.
Q-16
Which key ensures entity integrity?
Medium
Keys in a Relational Database
A
Foreign Key
B
Composite Key
C
Super Key
D
Primary Key
Answer: Primary Key
Explanation: Primary key ensures uniqueness.
Q-17
Which term refers to a row in a table?
Easy
Relational Data Model
A
Tuple
B
Attribute
C
Relation
D
Field
Answer: Tuple
Explanation: Row is called tuple.
Q-18
Which problem is solved by DBMS?
Medium
Database Management System
A
Data redundancy
B
Data duplication
C
Data inconsistency
D
All of these
Answer: Data duplication
Explanation: DBMS reduces redundancy and inconsistency.
Q-19
What will be number of attributes?
Easy
Relational Data Model
Sample Data
| A | B |
|---|
A
1
B
3
C
2
D
4
Answer: 2
Explanation: There are 2 columns.
Q-20
Which key references primary key of another table?
Easy
Keys in a Relational Database
A
Primary Key
B
Composite Key
C
Candidate Key
D
Foreign Key
Answer: Foreign Key
Explanation: Foreign key references another table.
Q-21
Which feature allows multiple users to access data simultaneously?
Medium
Database Management System
A
Concurrency
B
Redundancy
C
Security
D
Backup
Answer: Concurrency
Explanation: Concurrency allows multi-user access.
Q-22
Which of the following is a collection of related data?
Easy
Introduction
A
File
B
Database
C
Table
D
Attribute
Answer: Database
Explanation: Database is a collection of related data.
Q-23
Which key uniquely identifies records among multiple candidate keys?
Medium
Keys in a Relational Database
A
Foreign Key
B
Composite Key
C
Primary Key
D
Alternate Key
Answer: Primary Key
Explanation: Primary key is selected from candidate keys.
Q-24
Which system provides better security and integrity?
Easy
Database Management System
A
File System
B
Spreadsheet
C
Manual System
D
DBMS
Answer: DBMS
Explanation: DBMS ensures data security and integrity.
Q-25
Which key can have duplicate values?
Medium
Keys in a Relational Database
A
Foreign Key
B
Primary Key
C
Candidate Key
D
Super Key
Answer: Foreign Key
Explanation: Foreign key can have duplicate values.
Q-26
Which component organizes data into rows and columns?
Easy
Relational Data Model
A
File
B
Table
C
Database
D
Record
Answer: Table
Explanation: Table organizes data.
Q-27
Which system suffers from data inconsistency?
Easy
File System
A
DBMS
B
RDBMS
C
File System
D
Cloud DB
Answer: File System
Explanation: File systems often have inconsistency issues.
Q-28
Which term represents complete table?
Medium
Relational Data Model
A
Tuple
B
Attribute
C
Key
D
Relation
Answer: Relation
Explanation: Relation refers to entire table.
Q-29
Which key cannot contain NULL values?
Medium
Keys in a Relational Database
A
Primary Key
B
Foreign Key
C
Composite Key
D
Alternate Key
Answer: Primary Key
Explanation: Primary key must be unique and not NULL.
Q-30
Which model uses relations (tables) to represent data?
Easy
Relational Data Model
A
Hierarchical Model
B
Relational Model
C
Network Model
D
Object Model
Answer: Relational Model
Explanation: Relational model uses tables.
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