What is event sourcing and CQRS?
Event Sourcing and CQRS CQRS involves splitting an application into two parts internally — the command side ordering the system to update state and the query side that gets information without changing state..
What is Event Store in event sourcing?
Since saving an event is a single operation, it is inherently atomic. The application reconstructs an entity’s current state by replaying the events. Applications persist events in an event store, which is a database of events. The store has an API for adding and retrieving an entity’s events.
Why event sourcing is a bad idea?
CQRS + ES can make things a lot simpler in complex software systems by having rich domain objects, simple data models, history tracking, more visibility into concurrency problems, scalability and much more. It does require a different way thinking about the systems so it could be difficult to find qualified developers.
Why do we need event sourcing?
Event sourcing is a great way to atomically update state and publish events. The traditional way to persist an entity is to save its current state. Event sourcing uses a radically different, event-centric approach to persistence. A business object is persisted by storing a sequence of state changing events.