Informatics Practices

Textbook for Class XII

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 12149 – INFORMATICS PRACTICES ISBN 978-93-5292-361-8
Textbook for Class XII

First Edition
ALL RIGHTS RESERVED
December 2020 Agrahayana 1942
 No part of this publication may be reproduced, stored in a
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Reprinted without the prior permission of the publisher.
January 2023 Pausha 1944  This book is sold subject to the condition that it shall not, by
way of trade, be lent, re-sold, hired out or otherwise disposed
March 2024 Chaitra 1946 of without the publisher’s consent, in any form of binding or
cover other than that in which it is published.
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by a sticker or by any other means is incorrect and should
PD 50T SU be unacceptable.

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 Foreword
Information Technology has continuously been crossing the barriers of
access and communication and reaching more and more people. The number
of internet users in India has been on the rise. The tremendous growth in
computer science, telecommunications and information technology has
resulted in automation of various tasks and contributed to the ease of
living. Technology has made continuous inroads into diverse areas—be it
business, commerce, science, sports, health, transportation or education.
Today, we are living in an interconnected world where computer based
applications influence the way we learn, communicate, commute, or even
socialise.
With so many users of Information and Communication Technology
(ICT), huge volumes of data are continuously generated at an unprecedented
rate. Many innovative business models are being evolved which utilise such
data to reach potential customers in a more targeted way. Government
agencies are also using data to deliver services and fast track progress
of different programmes, strengthen accountability and to make more
informed decisions. This has been creating better opportunities for our
youth not only to enter the field of technical education but also in the
world of work. NCERT, for the first time, has developed a textbook on
‘Informatics Practices’ to develop skill sets in students to make use of the
opportunities provided by ICT.
This book focuses on the fundamental concepts related to handling of
data while opening a window to the emerging areas of data processing. It
seeks to address the dual challenges of reducing curricular load as well as
introducing the latest development in the field of ICT.
As an organisation committed to systemic reforms and continuous
improvement in the quality of its curricular material, NCERT welcomes
comments and suggestions to enable us to bring about necessary changes
in its further publications.

Hrushikesh Senapaty
Director
New Delhi National Council of Educational
August 2020 Research and Training

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 Preface
In the present education system of our country, specialised and
discipline based courses are introduced at the higher secondary stage.
This stage is crucial as well as challenging because of the transition
from general to discipline-based curriculum. The syllabus at this stage
needs to have sufficient rigour and depth while remaining mindful of the
comprehension level of the learners. Further, the textbook should not be
heavily loaded with content.
We are living in an era where information drives many of our socio
economic decisions. Millions of people are accessing internet round the
clock for availing various services and thereby generating vast amount of
data. Processing of data is becoming a key skill with applications across the
disciplines. Thus, study of basic concepts of data handling and analysis
is becoming more and more desirable. There are courses offered in the
name of Computer Science, Information and Communication Technology
(ICT), Information Technology (IT), etc. by various boards and schools up
to secondary stage, as optional. These mainly focus on using computer for
word processing, presentation tools and application software.
Informatics Practices (IP) at the higher secondary stage of school
education is also offered as an optional subject. At this stage, students
can take up IP with the aim of pursuing a career in data science or related
areas after going through professional courses at higher levels. Therefore,
at higher secondary stage, the curriculum of IP introduces basics of
database management systems and data processing. The book has seven
chapters covering the following broader themes:
• SQL Queries: Querying database using the Structured Query
Language by applying SQL functions including aggregate functions.
• Data Handling: The popular Python library called Pandas has been
introduced. The important data structures of Pandas – Series and
DataFrame have been covered in details and basic data handling
and data analysis using Pandas are included.
• Data Visualisation: The Pandas library called Pyplot is introduced.
It demonstrates how to generate high quality graphs and charts
from Python using the Pyplot tool.
• Internet and Web: Introduction to the concepts of Computer
networks are given, followed by a brief overview of Internet, its
application are given. The concept of web, website, and its hosting
is also included.
• Societal Impact: Awareness of digital footprints, data privacy and
protection, cyber crime, etiquettes, copyright and plagiarism,
E-waste in a digital society and their implications on security,
privacy, piracy, ethics, values and health concerns.

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 vi

Each chapter has two additional components — (i) activities and

(ii) think and reflect for self assessment while learning as well as to generate
further interest in the learner. A number of hands-on examples are given to
gradually explain methodology to solve different types of problems across
the Chapters. The programming examples as well as the exercises in the
chapters are required to be solved in a computer and verify with the given
outputs.
Box items are pinned inside the chapters either to explain related
concepts or to describe additional information related to the topic covered
in that section. However, these box-items are not to be assessed through
examinations.
Project Based Learning given at the end includes exemplar projects
related to real-world problems. Teachers are supposed to assign these or
similar projects to be developed in groups. Working in such projects may
promote peer-learning, team spirit and responsiveness.
The chapters have been written by involving practicing teachers as well
as subject experts. Several iterations have resulted into this book. Thanks
are due to the authors and reviewers for their valuable contribution. I would
like to place on record appreciation for Professor Om Vikas for leading the
review activities of the book as well as for his guidance and motivation
to the development team throughout. Comments and suggestions
are welcome.

New Delhi Dr. Rejaul Karim Barbhuiya

31 August 2020 Assistant Professor
Central Institute of
Educational Technology

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 Textbook Development Committee
Members
Anamika Gupta, Assistant Professor, Shaheed Sukhdev College of Business
Studies, University of Delhi
Anju Gupta, Freelance Educationist, Delhi
Anuradha Khattar, Assistant Professor, Miranda House, University of Delhi
Chetna Khanna, Freelance Educationist, Delhi
Harita Ahuja, Assistant Professor, Acharya Narendra Dev College,
University of Delhi
Mohini Arora, HOD (Computer Science), Air Force Golden Jubilee Institute,
Subroto Park, Delhi
Naeem Ahmad, Assistant Professor, Madanapalle Institute of Technology
and Science, Madanapalle, Andhra Pradesh
Naveen Gupta, PGT (Computer Science), St. Marks's Sr Sec Public School,
Meera Bagh, Delhi
Neeru Mittal, PGT (Computer Science), SRDAV Public School, Dayanand
Vihar, Delhi
Priti Rai Jain, Assistant Professor, Miranda House, University of Delhi
Sangita Chadha, HOD (Computer Science), Ambience Public School,
Safdarjung Enclave, Delhi
Sharanjit Kaur, Associate Professor, Acharya Narendra Dev College,
University of Delhi
Sugandha Gupta, Assistant Professor, Sri Guru Gobind Singh College of
Commerce, University of Delhi
Vineeta Garg, PGT (Computer Science), SRDAV Public School, Dayanand
Vihar, Delhi

Member-Coordinator
Rejaul Karim Barbhuiya, Assistant Professor, Central Institute of
Educational Technology, NCERT, Delhi

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 Acknowledgements
The National Council of Educational Research and Training acknowledges
the valuable contributions of the individuals and organisations involved in
the development of Informatics Practices textbook for Class XII.
The Council expresses its gratitude to the syllabus development team
including MPS Bhatia, Professor, Netaji Subhas Institute of Technology,
Delhi; T. V. Vijay Kumar, Professor, School of Computer and Systems
Sciences, Jawaharlal Nehru University, New Delhi; Zahid Raza, Associate
Professor, School of Computer and Systems Sciences, Jawaharlal Nehru
University, New Delhi; Vipul Shah, Principal Scientist, Tata Consultancy
Services, and the CSpathshala team; Aasim Zafar, Associate Professor,
Department of Computer Science, Aligarh Muslim University, Aligarh;
Faisal Anwer, Assistant Professor, Department of Computer Science,
Aligarh Muslim University, Aligarh; Smruti Ranjan Sarangi, Associate
Professor, Department of Computer Science and Engineering, Indian
Institute of Technology, Delhi; Vikram Goyal, Associate Professor,
Indraprastha Institute of Information Technology (IIIT), Delhi; and Mamur
Ali, Assistant Professor, Department of Teacher Training and Non-formal
Education (IASE), Faculty of Education, Jamia Millia Islamia, New Delhi.
The Council is thankful to the following resource persons for providing
valuable inputs in developing this book — D.N. Sansanwal, Retd. Professor,
Devi Ahilya Vishwavidyalaya, Indore; Veer Sain Dixit, Assistant Professor,
Atma Ram Sanatan Dharma College, University of Delhi; Mukesh Kumar,
DPS RK Puram, Delhi; Aswin K. Dash, Mother’s International School,
Delhi; Purvi Kumar, Co-ordinator, Computer Science Department, Ganga
International School, Rohtak Road, Delhi; Mudasir Wani, Assistant
Professor, Govt. College for Women, Nawakadal, Srinagar, Jammu and
Kashmir; Sajid Yousuf Bhat, Assistant Professor, University of Kashmir,
Jammu and Kashmir; Professor Om Vikas, Formerly Director, ABV-IIITM,
Gwalior, MP.
The council is grateful to Sunita Farkya, Professor and Head, Department
of Education in Science and Mathematics, NCERT and Amarendra P. Behera,
Professor and Joint Director, CIET, NCERT for their valuable cooperation
and support throughout the development of this book.
The Council also gracefully acknowledges the contributions of
Meetu Sharma, Graphic Designer cum DTP Operator; Kanika Walecha,
DTP Operator; Pooja, Junior Project Fellow in shaping this book. The
contributions of the office of the APC, DESM and Publication Division,
NCERT, New Delhi, in bringing out this book are also duly acknowledged.
The Council also acknowledges the contribution of Ankeeta Bezboruah
Assistant Editor (Contractual), Publication Division, NCERT for copy
editing this book. The efforts of Rajshree Saini, DTP Operator (Contractual),
Publication Division, NCERT are also acknowledged.

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 Contents
Foreword iii
Chapter 1 Querying and SQL Functions 1
1.1 Introduction 1
1.2 Functions in SQL 4
1.3 GROUP BY in SQL 14
1.4 Operations on Relations 16
1.5 Using Two Relations in a Query 19

Chapter 2 Data Handling using Pandas - I 27

2.1 Introduction to Python Libraries 27
2.2 Series 29
2.3 DataFrame 40
2.4 Importing and Exporting Data between CSV
Files and DataFrames 55
2.5 Pandas Series Vs NumPy ndarray 57

Chapter 3 Data Handling using Pandas - II 63

3.1 Introduction 63
3.2 Descriptive Statistics 65
3.3 Data Aggregations 75
3.4 Sorting a DataFrame 77
3.5 Group by Functions 79
3.6 Altering the Index 82
3.7 Other DataFrame Operations 84
3.8 Handling Missing Values 89
3.9 Import and Export of Data between Pandas
and MySQL 98

Chapter 4 Plotting Data using Matplotlib 105

4.1 Introduction 105
4.2 Plotting using Matplotlib 106
4.3 Customisation of Plots 108
4.4 The Pandas Plot Function (Pandas Visualisation) 112

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 x

Chapter 5 Internet and Web 137

5.1 Introduction to Computer Networks 137
5.2 Types of Networks 139
5.3 Network Devices 142
5.4 Networking Topologies 146
5.5 The Internet 148
5.6 Applications of Internet 149
5.7 Website 153
5.8 Web Page 154
5.9 Web Server 156
5.10 Hosting of a Website 157
5.11 Browser 158

Chapter 6 Societal Impacts 167

6.1 Introduction 167
6.2 Digital Footprints 168
6.3 Digital Society and Netizen 169
6.4 Data Protection 174
6.5 Creative Commons 178
6.6 Cyber Crime 179
6.7 Indian Information Technology Act (IT Act) 182
6.8 E-waste: Hazards and Management 183
6.9 Impact on Health 186

Chapter 7 Project Based Learning 195

7.1 Introduction 195
7.2 Approaches for Solving Projects 196
7.3 Teamwork 197
7.4 Project Descriptions 199

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