Why use MongoDB?

MongoDB is a free, fast, and scalable database with a JSON format and simple syntax. It enables flexible schemas and, thus, iterative and rapid development. MongoDB is able to accommodate data structures of varying complexities. Additionally, its querying and aggregation methods make it an excellent choice for a flexible REST API framework such as FastAPI, coupled with an official Python driver such as Motor. It has a high level of adoption and maturity and is one of the pillars of the NoSQL data storage movement that took the web development world by storm a decade ago.

The following are some other features that will be detailed for use in this book:

• Complex nested structures: MongoDB documents allow other documents and arrays of documents to be embedded, which naturally translates into the data flow of a modern data web app (for example, you can embed all comments into the blog post they respond to). Denormalization is encouraged.
• Simple, intuitive syntax: The methods for performing basic create, read, update, delete (CRUD) operations, coupled with powerful aggregation frameworks and projections, allow you to achieve almost all data reads quite easily through the use of drivers. The commands should be intuitive for anyone with a bit of SQL experience.
• Community and documentation: MongoDB is backed by a mature company and a strong community, and it offers various tools to facilitate the development and prototyping process. For instance, Compass is a desktop application that enables users to manage and administer databases. The framework of the serverless functions is constantly being updated and upgraded, and there are excellent drivers for virtually every programming language.

Of course, MongoDB is not a silver bullet, and some challenges are worth noticing upfront. On the one hand, the schema-less design and the ability to insert any type of data into your database might be a bit panic-inducing but translates to the need for stronger data integrity validation on the backend side. You will see how Pydantic—an excellent Python validation and type-enforcement library—can help you with stronger data integrity. The absence of complex joins, which are present in the SQL world, might be a dealbreaker for some types of applications.

Now that you understand what MongoDB brings to the table in terms of scalability and flexibility, with its schema-less approach, take a look at the REST API framework of choice, FastAPI, and learn how it can help you implement that schema-less approach and simplify your interactions with the data.