It'll happen eventually. Someone will come down with a feature request for your app to "create dashboards and reporting on our data". So how do you go about doing it? What parts of your database should you start thinking about differently? What is "reporting" anyway? Is ActiveRecord enough to pull this off?
Let's go on a journey through the world of Relational Online Analytical Processing (ROLAP) and see how this can apply to Rails. We'll also look at database considerations and finish with looking at a light DSL that works with ActiveRecord to help make your data dance.