ActiveRecord Serialization Gotcha

Gotcha when using ActiveRecord's serialize method (Rails 2.3.8).

Say you have an ActiveRecord backed Order model that looks something like this:

Where PricingParams is a non-ActiveRecord based model whose attributes include other ActiveRecord objects:

In order for Rails to properly unserialize the Order#pricing_params contents, you'll need to manually require the necessary ActiveRecord objects in the PricingParams class (as shown with the require statements in the snippet above). If you don't do this, then Order#pricing_params won't know how to respond to any of the Product or Price methods.

Took me a while to figure this out so hopefully this will save someone else some time.