MongoDB is a free and open-source NoSQL database program. It stores data in collections of documents where a document is like a row in the traditional relational database systems. It does not have a fixed schema for storing data in a collection; you store data in key-value pairs like a Python dictionary. The features like flexible data models and support for horizontal scaling allow you to make changes or scale the database as the requirements change. MongoEngine is an Object Document Mapper (OD......