Beginning Rails 6: From Novice to Professional

Appendix A: Databases 101

Let’s begin with some simple definitions. A database is a piece of software that governs the storage, retrieval, deletion, and integrity of data. Databases are organized into tables. Tables have columns (or, if you prefer, fields), and data are stored in rows. If you’re familiar with spreadsheets, then the idea is fairly similar. Of course, databases blow spreadsheets out of the water in terms of power and performance.

Some databases are relational—meaning they model their data in a way that makes use of relationships between tables. In this book, we use SQLite and Postgres, both of which are relational databases, and you may have seen already how we use these relationships to associate users with articles, for example. ...