Active Record CallbacksThis guide teaches you how to hook into the life cycle of your Active Record objects.After reading this guide, you will know: When certain events occur during the life of an Active Record object. How to register, run, and skip callbacks that respond to these events. How to create relational, association, conditional, and transactional callbacks. How to create objects that encapsulate common behavior for your callbacks to be reused.| Ruby on Rails Guides
When writing custom validators like described in the Rails guide on validations it’s good practice to write tests for them so you are sure they work as intended. Let’s take a look at the custom validator example shown in that Rails guide:| Mark's Blog
Active Record AssociationsThis guide covers the association features of Active Record.After reading this guide, you will know how to: Understand the various types of associations. Declare associations between Active Record models. Choose the right association type for your models. Use Single Table Inheritance. Setting up and using Delegated Types.| Ruby on Rails Guides
Active Record BasicsThis guide is an introduction to Active Record.After reading this guide, you will know: How Active Record fits into the Model-View-Controller (MVC) paradigm. What Object Relational Mapping and Active Record patterns are and how they are used in Rails. How to use Active Record models to manipulate data stored in a relational database. Active Record schema naming conventions. The concepts of database migrations, validations, callbacks, and associations.| Ruby on Rails Guides
