SQL vs. NoSQL: Choosing the Right Database

The same book can be stored in two very different ways. A relational database splits it into rows of separate tables, one for the book and one for its reviews, and joins them when you ask. A document database keeps the book and its reviews together as one JSON-like record. Both work, and each choice makes some queries easy and others harder.

This chapter connects an Express API for a small bookstore to both kinds of database. You will use MongoDB through the Mongoose library, then PostgreSQL through the Sequelize library