// thinkbeforecoding

Where are my Entities and my Repositories ?

2009-06-23T14:20-11 / jeremie chassaing

During Evans’ talk at ParisJug, some attendees where surprised that there was no mention of Entities or Repositories

Quite a lot of people where introduced to Domain Driven Design by these aspects and see these as the main advance of DDD.

In contrast, Eric Evans explained to me he had some regrets he placed these patterns so early in the book. Many readers think they know the most important at this point and stop reading after chapter 6.

Actually those patterns are only object model patterns that enable Separation of Concerns and Persistence Ignorance, but can also be used in context that are not Domain Driven at all like CRUD.

Of course, if you want to implement a domain independent of all infrastructure concerns, good OO practices will be required, but those practices won’t make your application Domain Driven (don’t understand that not following DDD would make your design a bad design… you apply DDD if you want and if you need to, but achieving persistence ignorance won’t mean you practice DDD.)

But you’ve more to learn from Strategic Design, Bounded Contexts and distillation of the Core Domain etc.