How to design great Aggregate Roots in Domain-Driven Design

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In this video, I'll do a deep dive into the theory behind Aggregates. I'm going to explain how to design an aggregate root and implement it in your .NET applications. The aggregate root pattern from Domain-Driven Design can help you create a better domain model. An aggregate acts as a consistency boundary and encapsulates one or more entities. Designing a good aggregate takes a lot of skill and practice.
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Chapters
0:00 What is an Aggregate?
1:05 Why do we need Aggregates?
2:15 What is an Aggregate (continued)
5:42 Aggregate design best practices
7:30 Let's look at an Aggregate example

[@MilanJovanovicTech]

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[@vantavoids]

honestly the fact that i was struggling all day with my aggregate roots and you happen to release a video talking about those specially... did you hide a mic under my desk?? other than that top tier video as per usual please keep it up

[@MilanJovanovicTech]

Glad it was helpful, and no worries I don't have a mic anywhere (or do I?)

[@sergiom.954]

The value of your content is unique. Thanks Milan

[@MilanJovanovicTech]

No, thank you! :)

[@wannadie9950]

awesome job milan, love you

[@MilanJovanovicTech]

Thanks a lot! :)

[@davidjiang7929]

Would you happen to have more examples on the unit of work and how to save aggregate to database?

[@MilanJovanovicTech]

Well, I've got a bunch of videos on the channel covering DDD aggregates directly or indirectly

[@victorgarcia3526]

Hey Milan, what if you push your code examples to github so we can check the code while watching the video?

[@MilanJovanovicTech]

I share the code on Patreon

[@user-ev9jg6ts6e]

Hi Milan. Nice video, appreciate it. Though not so good example on Workout aggregate, not showing any invariant between Workout and Exercises. Aggregate is about behavior and invariants and not about data.

[@MilanJovanovicTech]

Wanted to focus on maintaining a consistency boundary

[@alexramossilva]

Can you talk about Business Rule Engines and what are the design patterns appropriate to implement it?

[@MilanJovanovicTech]

Not familiar with them

[@ratanapouy]

Do you have this full course?

[@MilanJovanovicTech]

Not really (yet)

[@baranacikgoz]

The change you've done to the RemoveExercise method could not be left like that. You did not specified which Include's is used inside GetById method for Workout. If you decide to do that, it is wiser to conditionally include exercises of workouts by specifying exerciseId. Otherwise if there are millions of exercises you are loading all into memory just to remove one.

[@MilanJovanovicTech]

If there are a large number of exercises, we would implement this differently... But we could also impose a business constraint that a workout can have at most 30 exercises.

[@euler.chavez]

@@MilanJovanovicTech What is this process like, or what would it be like? The "basic" examples are easy to understand, but the complex cases and their variations are rarely explained. For example, in a context where the Family is the aggregate, with entities such as Members and Addresses: a) If I need to obtain only the members, do I always have to access the aggregate? b) If I want to filter address based on type (house, work, business, etc), do I have to do it through the aggregate?

[@ChristofferLund]

@@MilanJovanovicTech If you could provide an example of how you could elegantly solve this if the related entity has too many to load all into memory that would be nice. I find that to be one of the bigger challenges when using aggregates. Even just having a list of IDs could be too much at one point i presume