Book Image

Learning Mongoid

By : Gautam Rege
Book Image

Learning Mongoid

By: Gautam Rege

Overview of this book

Mongoid helps you to leverage the power of schema-less and efficient document-based design, dynamic queries, and atomic modifier operations. Mongoid eases the work of Ruby developers while they are working on complex frameworks. Starting with why and how you should use Mongoid, this book covers the various components of Mongoid. It then delves deeper into the detail of queries and relations, and you will learn some tips and tricks on improving performance. With this book, you will be able to build robust and large-scale web applications with Mongoid and Rails. Starting with the basics, this book introduces you to components such as moped and origin, and how information is managed, learn about the various datatypes, embedded documents, arrays, and hashes. You will learn how a document is stored and manipulated with callbacks, validations, and even atomic updates. This book will then show you the querying mechanism in detail, right from simple to complex queries, and even explains eager loading, lazy evaluation, and chaining of queries. Finally, this book will explain the importance of performance tuning and how to use the right indexes. It also explains MapReduce and the Aggregation Framework.
Table of Contents (14 chapters)
Learning Mongoid
About the Author
About the Reviewers

The Mongoid document

MongoDB stores documents that have fields and maybe other documents embedded in it. The documents are stored in collections. This is analogous to records stored in tables. The difference is that documents, unlike records in a SQL database, need not have the same structure or fields. In fact, as we have already seen in the previous chapter, there is no standard structure for storing documents in MongoDB.

So, do we define a default structure when we use Mongoid? Yes, not only can we define some basic default fields in a Mongoid document but we can also add fields dynamically (we saw this in the previous chapter). So we get the best of both worlds. If you have used ActiveRecord migrations earlier, remember that we don't need them anymore as we define the default fields in the model itself.

Documents are stored in the BSON format by MongoDB. BSON (Binary JSON) is a compact format that uses JSON standards for communication, and a serialized format for storage. This gives us...