Understanding the database

We commonly use the word database in different ways, but let’s be a bit more formal here:

A database is where we store our data, where we persist it (if we want), and where we can run some queries to insert new data and retrieve or modify existing data.

You might think that a filesystem fits this description, but actually, this is not the case; a real database allows us to perform very complex and precise queries to gather data based on very specific conditions. To do so, we will have a language to perform these queries or other operations. In our case, we will focus on a language called SQL.

We’ve stated what a database is, but this is still quite abstract. To create a database and fill it with data, we need an engine – essentially, an application – that will allow us to perform all these operations. In this section, we’ll learn how to use a database engine called Postgres SQL. As its name suggests, this engine...