Rich domain model with behaviours and ORM

Question

After watching NDC12 presentation \"Crafting Wicked Domain Models\" from Jimmy Bogard (http://ndcoslo.oktaset.com/Agenda), I was wandering how to persist that kind of domain mod

Answer 1

When doing DDD first thing, you ignore the persistence concerns. THe ORM is tighlty coupled to a RDBMS so it's a persistence concern.

An ORM models persistence structure NOT the domain. Basically the repository must 'convert' the received Aggregate Root to one or many persistence entities. The Bounded Context matters a lot since the Aggregate Root changes according to what are you trying to accomplish as well.

Let's say you want to save the Member in the context of a new offer assigned. Then you'll have something like this (of course this is only one possible scenario)

public interface IAssignOffer
{
    int OwnerId {get;}
    Offer AssignOffer(OfferType offerType, IOfferValueCalc valueCalc);
    IEnumerable NewOffers {get; }
}

public class Member:IAssignOffer
{
    /* implementation */ 
 }

 public interface IDomainRepository
 {
    void Save(IAssignOffer member);    
 }

Next the repo will get only the data required in order to change the NH entities and that's all.

About EVent Sourcing, I think that you have to see if it fits your domain and I don't see any problem with using Event Sourcing only for storing domain Aggregate Roots while the rest (mainly infrastructure) can be stored in the ordinary way (relational tables). I think CQRS gives you great flexibility in this matter.