Command-Query Responsibility Segregation (CQRS) by Example

Command-Query Responsibility Segregation (CQRS): by Example
English | 2020 | ISBN: n/a | 110 Pages | PDF EPUB | 12 MB
We think CQRS is the next natural step forward and we want to guide you through it.CQRS is usually discussed along with Event Sourcing, a pattern where application state is a projection of the Domain Events that happen through its lifetime. Event Sourcing relies on having a stream of Domain Events to reconstitute state. Something convenient for operations that modify the state of the application, known as Commands; however, querying the system requires some special mechanisms that aren't that trivial. We can say than in Event Sourced systems CQRS is mandatory in order to generate the required information to be able to query later, but the opposite isn't true. We can develop a CQRS system without Event Sourcing, so worry not, this book won't cover Event Sourcing.