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Questions tagged [event-sourcing]

Event Sourcing is a design pattern that captures all changes to an application's state as a sequence of events.

A design pattern publicized by Martin Fowler in which changes to application state are represented as events which contain snapshots of data that describe the change. See Event Sourcing at MartinFowler.com.

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Using Kafka as a (CQRS) Eventstore. Good idea?

Although I've come across Kafka before, I just recently realized Kafka may perhaps be used as (the basis of) a CQRS, eventstore. One of the main points that Kafka supports: Event capturing/storing, all HA of course. Pub/sub architecture Ability to…
Geert-Jan
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Using an RDBMS as event sourcing storage

If I were using an RDBMS (e.g. SQL Server) to store event sourcing data, what might the schema look like? I've seen a few variations talked about in an abstract sense, but nothing concrete. For example, say one has a "Product" entity, and changes to…
Neil Barnwell
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CQRS Event Sourcing: Validate UserName uniqueness

Let's take a simple "Account Registration" example, here is the flow: User visit the website Click the "Register" button and fill out the form, click the "Save" button MVC Controller: Validate UserName uniqueness by reading from…
Mouhong Lin
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What are the disadvantages of using Event sourcing and CQRS?

Event sourcing and CQRS is great because it gets rids developers being stuck with one pre-modelled database which the developer has to work with for the lifetime of the application unless there is a big data migration project. CQRS and ES also has…
user794783
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CQRS without Event Sourcing - what are the drawbacks?

Besides missing some of the benefits of Event Sourcing, are there any other drawbacks to adapting an existing architecture to CQRS without the Event Sourcing piece? I'm working on large application and the developers should be able to handle…
BuddyJoe
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EventStore vs. MongoDb

I would like to know what advantages there are to using EventStore (http://geteventstore.com) over implementing event sourcing yourself in a MongoDb. The reason I ask, is that our company has a number of people that work with MongoDb daily. They…
Jay Pete
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CQRS and Event Sourcing Difference

What is the difference between CQRS (Command Query Responsibility Segregation) and Event Sourcing? I believe Event Sourcing is a type of CQRS. What distinguishes each, and what makes Event Sourcing different from other types of CQRS? Thanks,
user8280126
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best event sourcing db strategy

I want to setup a small event sourcing lib. I read a few tutorials online, everything understood so far. The only problem is, in these different tutorials, there are two different database strategies, but without any comments why they use the one…
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Event Sourcing and Read Model generation

Assuming Stack Overflow domain problem and the following definition of events: UserRegistered(UserId, Name, Email) UserNameChanged(UserId, Name) QuestionAsked(UserId, QuestionId, Title, Question) Assuming the following state of event store (in the…
Dmitry Schetnikovich
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When to use an Eventstore

I am not quite sure I understood what an Eventstore is, I thought of it as some kind of "Transactionlog" for Domainobjects. What are the advantages/disadvantages of it and what are good scenarios to use it and when shouldn't it be used? EDIT: Since…
Bernhard Kircher
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Inter-Aggregate Communication in CQRS + DDD + Event Sourcing

How should separate aggregate roots (AR) communicate with one another in an environment built on DDD principles using an event-sourced aggregate back-end? For instance, I have a Facility aggregate root (AR) which has a factory method responsible for…
JD Courtoy
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Event Sourcing Resources

Looking for some suggestions for useful discussion groups, articles, success stories, reference apps, and tooling (.Net) on the subject of event sourcing. I am already familiar with: Fowler's article:…
Phil Sandler
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CQRS: Storing events and publishing them - how do I do this in a safe way?

As I've learned in Why is the CQRS repository publishing events, not the event store? it's the CQRS repository's task to publish events. So far, so good. Of course, storing the events and publishing them should be within one single transaction.…
Golo Roden
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Axon Framework vs Eventuate comparison

We are currently doing some research about CQRS and Event Sourcing and found two major frameworks taking care of these two concerns: Axon Framework and Eventuate. Both are continuesly developed, while Eventuate is now more actively developed in the…
Stefano L
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How to manage ViewModel changes in a CQRS + Event Sourcing Architecture

We are currently evaluating CQRS and Event Sourcing architectures. I am trying to understand what the maintenance implications of using this kind of design are. Two questions I am struggling to find answers to are this: 1) What happens if, after…
James
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