Introduction to MongoDB CHAPTER 1 Welcome to MongoDB. This document provides a brief introduction to MongoDB and some key concepts. See the installation guides (page 5) for information on downloading and installing MongoDB. 1.1 What is MongoDB 1.1.1 Document Database MongoDB is an open-source document database that provides high performance, high availability, and automatic scaling. A record in MongoDB is a document, which is a data structure composed of field and value pairs. MongoDB docu- ments are similar to JSON objects. The values of fields may include other documents, arrays, and arrays of documents. The advantages of using documents are: • Documents (i.e. objects) correspond to native data types in many programming languages. • Embedded documents and arrays reduce need for expensive joins. • Dynamic schema supports fluent polymorphism. 3