In Chapter 1, Introduction, we provide some background about MongoDB: why it was created, the goals it is trying to accomplish, and why you might choose to use it for a project. We go into more detail in Chapter 2, Getting Started, which provides an introduction to the core concepts and vocabulary of MongoDB. Chapter 2 also provides a first look at working with MongoDB, getting you started with the database and the shell.

The next two chapters cover the basic material that developers need to know to work with MongoDB. In Chapter 3, Creating, Updating, and Deleting Documents, we describe how to perform those basic write operations, including how to do them with different levels of safety and speed. Chapter 4, Querying, explains how to find documents and create complex queries. This chapter also covers how to iterate through results and options for limiting, skipping, and sorting results.

The next three chapters go into more complex usage than simply storing and retrieving data. Chapter 5, Indexing, explains what indexes are and how to use them with MongoDB. It also covers tools you can use to examine or modify the indexes used to perform a query, and it covers index administration. Chapter 6, Aggregation, covers a number of techniques for aggregating data with MongoDB, including counting, finding distinct values, grouping documents, and using MapReduce. Chapter 7, Advanced Topics, is a mishmash of important tidbits that didn’t fit into any of the previous categories: file storage, server-side JavaScript, database commands, and database references.

The next three chapters are less about programming and more about the operational aspects of MongoDB. Chapter 8, Administration, discusses options for starting the database in different ways, monitoring a MongoDB server, and keeping deployments secure. Chapter 8 also covers how to keep proper backups of the data you’ve stored in MongoDB. In Chapter 9, Replication, we explain how to set up replication with MongoDB, including standard master-slave configuration and setups with automatic failover. This chapter also covers how MongoDB replication works and options for tweaking it. Chapter 10, Sharding, describes how to scale MongoDB horizontally: it covers what autosharding is, how to set it up, and the ways in which it impacts applications.

In Chapter 11, Example Applications, we provide example applications using MongoDB, written in Java, PHP, Python, and Ruby. These examples illustrate how to map the concepts described earlier in the book to specific languages and problem domains.

Appendix A, explains MongoDB’s versioning scheme and how to install it on Windows, OS X, and Linux. Appendix B, includes some useful shell tips and tools. Finally, Appendix C, details a little about how MongoDB works internally: its storage engine, data format, and wire protocol.

Thanks to all of my co-workers at 10gen for sharing your knowledge and advice on MongoDB (as well as your advice on ops, beer, and plane crashes). Also, thank you, Mike, for magically making half of this book appear and correcting some of my more embarrassing errors before Julie saw them. Finally, I would like to thank Andrew, Susan, and Andy for all of their support, patience, and suggestions. I couldn’t have done it without you guys.

Thanks to all of my friends, who have put up with me during this process (and in general). Thanks to everyone I’ve worked with at 10gen for making working on MongoDB a blast. Thank you, Kristina, for being such a great coauthor. Most importantly, I would like to thank my entire family for all of their support with this and everything I undertake.