What is an event

By Yves Goeleven / On 2023-08-11 10:00:00 / 3 Minutes Read

Many developers have the wrong mental model of an event.

Very often they think about an event as 'something that happened in the system'.

This definition isn't ideal, as it only allows to represent state changes.

A better definition is:

An event represents a meaningfull business decission taken, which alters the state of the system.

This definition allows to represent these decissions explictly and let the system adapt to them.

This makes distributed systems design a lot easier, and opens up new opportunities as well. a.o. polyglot persistence.

Examples

Bad: SalesOrderChanged, DeliveryCreated
Good: SalesOrderBooked, DeliveryConfirmed

About the author

YVES GOELEVEN

I love to build web and cloud apps and have been doing so for the past 20 years.

My main areas of expertise are progressive web applications, event driven architecture, domain driven design, event sourcing, messaging, and Microsoft Azure.

Through this blog I hope to share some of this experience with you.

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