Duncan Jones comments

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                                            Duncan Jones

Problem: Patterns for something something must be unique

For sharding you need the email hash to be the shard key (partition key in azure tables) That last part (_if email XYZ is claimed, XYZ is released , XYZ...

Problem: What is the purpose of a domain (or service)

So do I understand it in a sort of inside/outside differentiator which is used to add clarity: e.g. "Inside this domain, the word Credit means .... " (not a million...

Problem: Define CorrelationId/CausationId patterns for Events

One thing I have done is have a wrapper **context** for each event which stores the things that are about the event (like causation and correlation identifiers, and timestamps, and...

Problem / suggestion: Comparison of event driven architecture v notification v pull on demand

Also - what is a good way to visualise these flowing states?

Problem: how to write this book

At the very least, examples need to be programming language agnostic... something I have had difficulty with.

Problem: Do We Need DDD Tactical Patterns when Doing EventSourcing ?

The most common recipe seems to be DDD -> Microservices -> EDA -> CQRS -> Event Sourcing. It does make sense for many systems, but any one of these components...

Problem: Define AsOf / AsAt

(Often used in accounting) These terms indicate that the state being returned is what it was at a particular point in time. In event sourcing this can be returned by...

Problem: Dealing With the Outside World (we need to get something done in the outisde world)

There are abstract entities in lots of businesses that do represent a form of **saga** pattern (with names like "booking" or "transaction" etc.) and for these the state of them...

Problem: Define consistent/consistency

"consistent" is perhaps more nebulous than "consistency" For example - does the data in the application tie in to some independent measure is one way of saying the system is...

Problem: Do We Need DDD Strategic Patterns When Doing EventSourcing ?

I guess this rather depends on the question **Is Event Sourcing an architecture ?** I would argue that it isn't (so it doesn't need DDD strategic patterns) but also add...