How to handle unique constraint with user friendly message about sample-dotnet-core-cqrs-api HOT 2 CLOSED

If for certain use cases you expect concurrent calls whose simultaneous write breaks business rules, you can use one more method besides the methods you mentioned - repeat command processing.

Then validation on the command handler / domain model will detect broken rule (because side effect of another command is already persisted) and the application will return an appropriate message.

The important thing is to have always all validation on the application side and treat database as "last line of defense" against such situations.

You can use the Polly library to implement this behavior

from sample-dotnet-core-cqrs-api.

The important thing is to have always all validation on the application side and treat database as "last line of defense" against such situations.

I think this is a good idea. It helped me a lot.

from sample-dotnet-core-cqrs-api.