Domain Modeling Made Functional

Fighting the Impulse to Do Class-Driven Design

If you’re an experienced object-oriented developer, then the idea of not being biased to a particular database model will be familiar, Indeed, object-oriented techniques such as dependency injection encourage you to separate the database implementation from the business logic.

But you, too, may end up introducing bias into the design if you think in terms of objects rather than the domain.

For example, as Ollie is talking, you may be creating classes in your head, like the figure.

Letting classes drive the design can be just as dangerous as letting a database drive the design—again, you’re not really ...