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Question

I have a question regarding DDD and the repository pattern.

Say I have a Customer repository for the Customer aggregate root. The Get & Find methods return the

Answer 1

I think that you only want to display summarized information. These bits of summarized information are no entities or value objects of the domain model. They are only information, nothing more.

It is something like showing reporting information. If I deal with such things, I would not stick to the pure DDD approach. Your suggested options are OK, because it's getting your job done. DDD should be not treated as dogma. Think outside the box. Loosen up a bit DDD.

But be aware that you are just creating informational values outside the model for displaying purpose. So if a user selects one bit of information to make some operation with it (which is defined in the domain model), you need to extract the identifier from the informational values and pull out the entity/value object/aggregate from a repository.

I strongly recommend this video: Eric Evans: What I've learned about DDD since the book. If you read his book, you really should see the whole video. Pay very close attention at about time 30:00 where Eric Evans himself talks about aggregates and refers to the problem you currently have.

Answer 2

I would:

1. Return a different object that represents a view of my object for display, e.g. CustomerInfo.
2. Return a DataTable. Often a generic container is the easiest and best way to go.

If the T in your generic base repository is a Customer, then I think you are mis-applying the concept of aggregate roots, though I'm not a strict Evansangelist. I would design a repository for Customer that returned any data that logically or comfortably groups with Customer, including DataTables or read-only objects that are views of Customer data.