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

Configuring relationships

Before we study the methods in detail, we need to understand that all relations can specify the parameters that configure the relation. Each relation follows the following pattern:

  • name: This is the mandatory name of the relation and is a symbol by which the relation will be referenced.

  • options: This is a hash that is used to configure the relation.

  • block: This is an optional block of code to configure some relations.

Common options for all relations

The following options are common to all relations:

  • :class_name: This is the class name if it cannot be determined from the name.

  • :inverse_of: This is the reverse relation, it is very important for creating or embedding relations.

  • :extend: If we need to configure the relation by passing a block, a module is created on the fly with this block and the relation class then extends from this module.

  • :inverse_class_name: This is used to determine the foreign key.

  • :name: This is the name of the relation.

  • :relation: This is the type of...