CQRS : Command & Query Responsibility Segregation Pattern
DDD has changed our modeling approaches. Eric Evans book has lead to a variety of innovative ideas such as DCI (Data Context Integration) and recently Erick Flemming introduced me to CQRS. I’ve spent the past few days running around the web consolidating a resource packet. Here are the links I’ve read and recommend:
Unshackle Your Domain
: Greg Young > InfoQ Link : Nice video but long (1 hour)
Clarified CQRS
: Udi Dahan’s righteous post on his blog here. Nice graphic.
CQRS à la Greg Young
An even more detailed / concrete post by Mark Nijhof that can be found here http://elegantcode.com/2009/11/11/cqrs-la-greg-young/comment-page-1/#comments. He ahs great hand drawn diagrams (previewed below, but the code is the best part… real working example)
> He has a working example of a banking application (winforms) here: http://github.com/MarkNijhof/Fohjin
> And a video on vimeo here: http://vimeo.com/7838858
Domain-Driven Design (the book)
Don’t forget Eric Evans DDD book that you can find here:http://www.amazon.com/Domain-Driven-Design-Tackling-Complexity-Software/dp/0321125215/ref=sr_1_1?ie=UTF8&s=books&qid=1270092554&sr=8-1
Other articles & frameworks
Sadly there are currently no .NET CQRS frameworks I could find. That said there are some Java. The front runner seems to be.
axonframework : CQRS Framework for Java
They have great documentation and a similar diagram as Mark (minus a command bus)
http://code.google.com/p/axonframework/
On InfoQ: http://www.infoq.com/articles/cqrs_with_axon_framework
EventSourcing & Snapshots
http://jonathan-oliver.blogspot.com/2009/03/event-sourcing-and-snapshots.html
Asynchronous Event Sourcing using Actors (SCALA)
Article : http://jonasboner.com/2009/02/12/event-sourcing-using-actors.html