Ivan
Ivan

Reputation: 1284

Should value object hold reference to entity?

Should value object hold reference to entity in DDD methodology?

EDIT

@Dmitry:

This is probably my case. Here I attach class diagram where the Account hold references to collection of IInvoiceable items. I treat with Tenant as entity, but it owns only 1 account and i dont think that Account needs identity. its part of Tenant. Or should I treat it as Entity? To me it doesnt make sense.

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Upvotes: 26

Views: 8063

Answers (2)

Dmitry
Dmitry

Reputation: 17350

Yes it can. This would be a relatively obscure case but DDD allows for it and it can be useful. From the DDD book by Eric Evans:

VALUE OBJECTS can even reference ENTITIES. For example, if I ask an online map service for a scenic driving route from San Francisco to Los Angeles, it might derive a Route object linking L.A. and San Francisco via the Pacific Coast Highway. That Route object would be a VALUE, even though the three objects it references (two cities and a highway) are all ENTITIES.

page #98

Upvotes: 45

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