cqrs

If using CQRS and creating an entity, and the values of some of its properties are generated part of the its constructor (e.g. a default active value for the status property, or the current datetime for createdAt ), how do you include that as part of your response if your command handlers can’t return values? You would need to create guid before creating an entity, then use this guid to query it. This way your command handlers always return void. [HttpPost] public ActionResult Add(string name) { Guid guid = Guid.NewGuid(); _bus.Send(new CreateInventoryItem(guid, name)); return RedirectToAction

I've read this nice post from Jonathan Oliver about handling out of order events. http://blog.jonathanoliver.com/cqrs-out-of-sequence-messages-and-read-models/ The solution that we use is to dequeue a message and to place it in a “holding table” until all messages with a previous sequence are received. When all previous messages have been received we take all messages out of the holding table and run them in sequence through the appropriate handlers. Once all handlers have been executed successfully, we remove the messages from the holding table and commit the updates to the read models. This

I am wondering how granular should a domain event be? For example I have something simple, like changing the firstName, the secondName and the email address on a profile page. Should I have 3 different domain events or just a single one? By coarse grained domain events when I add a new feature, I have to create a new version of the event, so I have to add a new event type, or store event versions in the event storage. By fine grained domain events I don't have these problems, but I have too many small classes. What do you think, what is the best practice in this case? What's the problem with

When using distributed and scalable architecture, eventual consistency is often a requirement. Graphically, how to deal with this eventual consistency? Users are used to click save, and see the result instantaneously... with eventual consistency it's not possible. How to deal with the GUI for such scenarios? Please note the question applies both for desktop applications and web applications. PS: I'm working with the Microsoft platform, but I imagine the question applies to any technology... A Task Based UI fits this model great. You create and execute tasks from the UI. You can also have