Keep your controllers clean and forms flexible by adding virtual attributes to your model. This very powerful technique allows you to create form fields which may not directly relate to the database.

You can pass more than simple strings to find conditions. Arrays, ranges, and nil values can be passed as well. In this episode you will see the tricks involved with passing these odd objects to find conditions. (Update: audio fixed).

Did you know ActiveRecord provides class methods for performing calculations on models? You can even use these methods through associations.

Be careful when storing a model in a session. It will behave differently than you expect and can easily get out of sync with the database. Instead of storing the model directly in the session, store the id to the model and use that to fetch it from the database.

In the final part of this series you will see how to refactor your tests. Keeping tests clean is important because it will make testing easier to do in the future.

Testing and refactoring go hand in hand. Refactoring is all about improving code without changing its behavior. Testing is all about making sure you don't change the behavior while you are improving the code.

Learn how to clean up your code through refactoring. This episode will show you how to move code from the view into the model to remove duplication and simplify the view.

Are you accepting sensitive user data? Passwords, credit card numbers, etc. By default, Rails stores all submitted parameters in plain text in the logs. This episode will show you how to filter this sensitive input so it doesn't show up in the log file.

If you want to change something in the layout on a per-template basis, content_for is your answer! This allows templates to specify view code that can be placed anywhere in a layout.

Everything you wanted to know about layouts: global layouts, controller layouts, shared layouts, dynamic layouts and action layouts. Yes, there really are that many ways to specify a layout.