(In this book, Peter, eelco plugin, Tim Hawkins and I want to fully demonstrate our experience of learning from mongodb: teach you how to use mongodb while keeping the design simple and clear. Each chapter provides a separate sample database, so you can read this book in a modular or linear way; It's entirely up to you. This means that you can skip some chapters as needed without affecting your study of other contents.The example commands in this book will appear in their output. They will be displayed in equal width "code" font and in bold to distinguish them from other result outputs. In most chapters, you will encounter tips, warnings, and notes that contain useful and sometimes extremely important information.)