1 Introducing databases and SQL

 

In this chapter

  • You get a foundation for the rest of the book.
  • You learn the basics of relational databases.
  • You peek into database design.
  • You write your first SQL query and learn more about the basics of SQL.
What you need to know

As you read this chapter, you will find some code snippets. If you want to execute those code snippets or see what changes need to be made to the code for different relational database management systems (RDBMSs), check the GitHub repository that accompanies this book (https://github.com/Neo-Hao/grokking-relational-database-design). You can find the scripts for this chapter in the chapter_01 folder; follow the instructions in the README.md file to run the scripts.

Overview

Database design is a critical yet easily neglected step in software development. Nearly every application requires data storage and management to some extent, but not every application has a well-designed database. If you design a database without knowing the principles of effective database design, your application may suffer from problems you weren’t expecting, such as disorganized data or queries that take too long and too many resources to run. These problems can lead to bugs and a bad user experience.

Relational databases

Tables, entities, and primary keys

Relational database management systems and SQL

Your first SQL query

The basics of SQL queries

Filtering

Aggregation

Table and data management

Create tables and add data to tables

Alter and drop tables

Recap

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