Separating behavior and persistence in models

Link: Separating behavior and persistence in models

— @engineyard via @lukebayes

Recall the Single Responsibility Principle: “There should never be more than one reason for a class to change.” As we commonly use them, ActiveRecord and DataMapper1 classes almost always violate this principle. There are usually at least two responsibilities handled by every AR/DM model: persistence and business logic. Carrying around that persistence behavior, and all the dependencies that go along with it, is what bloats and slows down our specs.