Event storming - oleksiyp/oleksiyp.github.io GitHub Wiki

Event Storming is a workshop format for quickly exploring complex business domains. DDD practice

Invite the right people to the workshop. Ideally you’ll want a large meeting room with 6..8 people, with the right mixture of the ones who know the questions to ask (and which are curious to listen to the answer) and the ones who know the answers.

Provide unlimited modelling space. Too often complex problems are not properly analysed because there’s not enough space available to see the problem. Your problem is bigger than your whiteboard, so what? My solution is to hack the modelling space using whatever available (my favorite tool is an Ikea paper roll) to get rid of the space limitation.

Explore the domain starting from Domain Events. A Domain Event is something meaningful happened in the domain. It can be easily translated into software, but the real value here is that it could be quickly grasped from non technical people. An event might be the predecessor of the follower of another one. Place all of them onto your modelling surface (the convention is to use orange stickies for this purpose) according to a timeline.

Explore the origin of Domain Events. Some events are the direct consequence of a user action —> represent it as a Command using a blue sticky note. Others are the consequence of something happening in external systems or of the time passing, we’ll use a purple sticky note for them. In some other cases, we’ll have events that will be the direct consequence of some other events. We’ll simply place the two events close together.

Look for Aggregates. Instead of defining aggregates starting from the code, we’re taking an outside-in approach: the Aggregate is the portion of the system that receives commands and decides whether to execute them or not, thus producing a domain event.

http://ziobrando.blogspot.com/2013/11/introducing-event-storming.html