CQRS-DDD-ReadModel-Queries in write model?

[Marcos Vitali]

Hi, I am using CQRS pattern with Micro ORM for reads and ORM for Writes. 

My question is about Queries in DDD in write model.

is it ok if I need to validate some information with a query in an aggregate complex business logic using the DDD WriteModel?

Thanks, Marcos.

[Tomas P.]

Hi Macros,

what exactly do you need to validate during a Query?

Best,

Tomas

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[Erik Landvall]

Hej Marcus

I think validation policies are best defined in the core domain model, used by the anti-corruption layer (the context-mapper). I have more success when the AC is located in the domain, instead of the infrastructure model. 

But really, this is modelling, you should design your component from the perspective of where the defined policies are less likely to create redundancy. 

However, speaking from an orchestration perspective, I consider it a better design when the lower level component is responsible for the business policies.

Regards

Erik Landvall

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[Marcos Vitali]

Erik, thanks for your answer. I agree with you, but my problem is not where I put my validation. My Aggregates are very robust, and all methods have guard clauses, business validations, "tell don't ask", additionally my Commands and Queries has basic validations duplicates yes sometime you need to break DRY in the real world and keep it real.

My question is about CQRS and core domain validation that return data. Is it ok to return data from aggregate when you use CQRS, because I feel validations as queries in the core domain and not in the Read Model.

 Thanks in advance.

On Mon, Jan 11, 2021 at 10:06 PM Marcos Vitali <marcos...@gmail.com> wrote:

Tomas P

Any validation that needs to return data, as in the example in the DDD red book shows, page 269 to 279 Authorize User return a value object UserDecriptor. I think the validations that returns data are not Read Model, so i did this in my domain with a query

Thanks in advance.

To view this discussion on the web visit https://groups.google.com/d/msgid/dddcqrs/CACLFiRCtNqXKZK%2B8ERS_G53kR8KMvibsMd5Z6PvvBCBiUsr-3g%40mail.gmail.com.

[Marcos Vitali]

Tomas P

Any validation that needs to return data, as in the example in the DDD red book shows, page 269 to 279 Authorize User return a value object UserDecriptor. I think the validations that returns data are not Read Model, so i did this in my domain with a query

Thanks in advance.

On Mon, Jan 11, 2021 at 4:32 PM Erik Landvall <er...@landvall.se> wrote:

To view this discussion on the web visit https://groups.google.com/d/msgid/dddcqrs/CACLFiRCtNqXKZK%2B8ERS_G53kR8KMvibsMd5Z6PvvBCBiUsr-3g%40mail.gmail.com.

[Erik Landvall]

I can't really grasp what you are asking, so I think I leave the thread, but good luck.

Erik Landvall

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To view this discussion on the web visit https://groups.google.com/d/msgid/dddcqrs/CAA%3Dt3BY89sV_kmZVt2PzjBRqUTUpfDXkTUfAPpDgpDUUXfVZ-Q%40mail.gmail.com.