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Preface

This book aims to be an introduction to SQL, the query language we use to interact with relational databases.

This book was published in late 2024.

Legal

Flavio Copes, 2024. All rights reserved.

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Introduction

The goal of this handbook is to get you up and running with SQL, starting from zero knowledge.

You will learn the terms and the main ideas, what is a DBMS, how to structure a database, how to insert data into it, how to query the database.

I will only teach you the basics, and once you’re done with this you’ll have the knowledge you need to dive deeper.

I called this “SQL Handbook” but I assume zero database knowledge, so I’m first going to give you an introduction to databases, in particular relational databases.

Information systems, data and information

The modern world is completely centered around information and data.

What's the difference between information and data?

Data is a singular unit of knowledge. It has no intrinsic value on its own. We can't extract meaning out of it, without knowing more about it.