DDD: Storing reference to non-Aggregate Root Entity from different Bounded Context

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I'm struggling to understand how to model my problem:

  • A Company can have many Teams.
  • Each Team must have a unique name per Company.
  • Reports for a particular Team must be retrievable, along with a list of all reports for a Company.

Just now, I have 3 Bounded Contexts's - Company, Team and Report. I believe I should move Team inside Company to enforce my unique name invariant - however, as I understand it:

"Nothing outside the Aggregate boundary can hold a reference to anything inside, except to the root Entity".

If I can only reference an AR from my Report AR, I cannot store which Team my report belongs to - just the company.

I have considered that Team may exist as it's own BC and also within the Company BC. Creation of a Team would then only happen from within the Company BC as an Entity. Here, the naming and invariant enforcement of that Team name can be ensured. The Team BC would then still exist and a Report can still hold reference to the TeamId from the Report AR. However, this would result in duplication of TeamId and TeamName - both within the Company BC and Team BC.

Does this approach sound ok, or am I missing something?

I'm confused if I have 3 BC's that should be 2 BC's, or missing a Team Entity concept within Company BC.

Maybe I'm confusing Bounded Contexts I only have/need Aggregate Roots - I'm not sure!

Gulp, help!

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domain-driven-designdomain-modelaggregaterootbounded-contexts
I suggest you read up on DDD so that the difference between BC's and Aggregates becomes clearer -- there might indeed be a confusion right now. – guillaume31
@acairns Did you come up with a solution for your problem? – JasonlPrice

1 Answers

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In your example Company and Team cannot be Bounded Contexts, it is entity (Company or Team can be Aggregation Root, it depends on the task), Company has Name identity, Team has CompanyName + TeamName identity.

Bounded Context is a cohesive set of models, which should reflect the meaning of the selected subdomain. Team and Company can form one BC, Reporting is another context.

If in your example Reporting is simply aggregate some information for easy display to the user, then this Reporting Bounded Context doesn't contain any Aggregation Roots, because there's no business logic and rules. In Reporting you should use simple DTOs to display the data.