Mongoid is a polished, high-level Ruby gem for accessing MongoDB. Here I cover installation, adding fields, validations, associations, and keys. (11 minutes)

It is important to use attr_accessible for security with mass assignment, but what if you need it to be dynamic based on user permissions? See how in this episode. (9 minutes)

In Rails 3 the non-database functionality of Active Record is extracted out into Active Model. This allows you to cleanly add validations and other features to tableless models. (6 minutes)

MongoDB is a document based database engine. Learn how to access it through MongoMapper in this episode. (13 minutes)

Use a virtual attribute to implement a simple tagging feature. In this episode I show you how to assign virtual attributes through a callback instead of a setter method. (7 minutes)

This episode will show you how to make a model which isn't based on Active Record. You may want to do this if a resource isn't backed by the database. (12 minutes)

If you have a lot of logic associated with the data inside a session, you'll need some central location to put this logic. See how to create a session based model in this episode. (13 minutes)

The scope_out plugin will generate several helpful find methods for you automatically! It's the best way to move the find conditions into your model. Watch this episode for details. (6 minutes)

In this third and final episode on complex forms I will show you how to edit a project and multiple tasks all in one form. This includes removing and adding tasks dynamically as well. See the show notes for updated code. (16 minutes)