In the conversation with Jana Beispiel you collected the office's words. A conversation between two people has limits, though: you hear only what the one person happens to be thinking of, and you never notice contradictions between two experts. Event storming brings everyone into one room and puts the whole process on a wall, so everybody sees what is missing and where people contradict each other.
The method comes from Alberto Brandolini. It has three levels: the big picture of a whole area of the business, the processes in detail and the design of the software. In this lesson you storm the big picture: from the first hint of a tender to the won quote. In lesson 4.2.3 you take a section of it in detail.
What an event is
The building block of event storming is the domain event: something that has happened in the domain and matters to the experts. Three questions decide whether a note is an event:
- Has it happened? An event is in the past tense: “Quote sent”, not “Send quote”.
- Would the expert tell somebody about it? Jana tells “Award granted” right away. “Record saved” she doesn't.
- Did something change afterward? After “Quote sent”, nobody may change anything about the quote anymore. That is a real difference.
An event almost always has the form noun plus past participle: “Tender imported”, “Decision to bid made”,
“Binding period expired”. The noun comes from the glossary. In the code, the same sentence later becomes English with a code name: “Quote sent”
becomes QuoteSent. That is what module 4.3 is about. For now only the language of the experts counts.
What is not an event ends up on the wall anyway while storming, and that's fine. You recognize it and rewrite it:
| Note | What it is | Rewritten |
|---|---|---|
| Send quote | a command, a wish to do something | Quote sent |
| Quote is open | a state, not something that happened | the event that starts the state: Quote drafted |
| Button “Send” clicked | operation, not business | Quote sent |
| Row saved in table | technology | leave it out, or look for the business event behind it |
| Watch the deadline! | a rule or a reminder | a hotspot: What happens when the deadline passes? |
Some events are triggered by nobody but by time: “Submission deadline passed”, “Binding period expired”. They are as important as the others, often even more so, because deadlines and trouble hang on them.