Service Bus for Windows Server
Move over MSMQ, Service Bus for Windows Server was recently released. Apparently it has been for awhile now (Oct 2012 release). I’m just late to the party I guess. Service Bus 1.0 was designed to...
View ArticleCAP Theorem, CQRS and Eventually Consistent
First, if you haven’t heard of Eric Brewer’s CAP theorem, it basically states that you can must choose two of three: Consistency Availability Partition Tolerance CQRS doesn’t solve CAP issues, however...
View ArticleCQRS Tech Talk Slides
Slides from my CQRS Tech Talk @ Hackforge. Command Query Responsibility Segregation (CQRS) from Derek Comartin The post CQRS Tech Talk Slides appeared first on CodeOpinion.
View ArticleEvent Sourcing Tech Talk Slides
Slides from my Event Sourcing Tech Talk @ Hackforge. Event Sourcing from Derek Comartin The post Event Sourcing Tech Talk Slides appeared first on CodeOpinion.
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Query Objects instead of Repositories
The repository pattern is often used to encapsulate simple and sometimes rather complex query logic. However, it has also been morphed into handling persistence and is often used as another layer of...
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Query Objects with a Mediator
In my previous blog Query Objects instead of Repositories, I demonstrated creating query objects and handlers to encapsulate and execute query logic instead of polluting a repository with both read...
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Eventual Consistency and Business Alignment
I recently discovered through eventual consistency that my bounded contexts were not properly aligned with the business. I won’t lie, it took me quite a while to make this realization. This was most...
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Clean up your Domain Model with Event Sourcing
I recently had a discussion with a developer who was new to Domain Driven Design, CQRS and Event Sourcing. They were using Greg Young’s Simple CQRS Example to create there own simple app as learning...
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How to get started with CQRS & Event Sourcing
When I first heard about CQRS & Event Sourcing concepts through various blogs and videos, primarily from Greg Young and Udi Dahan, I wanted to apply it everywhere. It seems really natural to want...
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Event Stream as a Message Queue
I was recently having a discussion around a system being built using Microsoft Azure. Some concepts being discussed for this system where CQRS, Event Sourcing and Message Queue. The diagram below is...
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Event Store Persistent Subscriptions
One of the really nice features of Event Store is the Persistent Subscriptions that were implemented in v3.2.0. I was previously using catch-up subscriptions but needed the ability to have many worker...
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Event Store Persistent Subscriptions Demo
In my previous blog post, I talked about Catch-Up Subscriptions in-comparison to Persistent Subscriptions in Event Store. I’ve been meaning to create a little demo as I didn’t find very much in my...
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Thin Controllers with CQRS and MediatR
I’m not a fan of fat controllers. One of the reasons I dislike having my core application logic in controllers is because I like using the web frameworks for what they are good at in my context. My...
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Identify Commands & Events
Once I started down the path of segregating commands and queries, I soon enough ran into a few issues that I needed to solve. Identifying Commands & Events Correlating Commands & Events...
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Idempotent Commands
Idempotence is the property of certain operations in mathematics and computer science, that can be applied multiple times without changing the result beyond the initial application. When you click the...
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Idempotent Aggregates
This blog post will cover creating Idempotent Aggregates and is apart of a series of posts related. Please take a look any previous posts as they may give more context to the code samples below. Thin...
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Organize by Feature
This post is about how I organize by feature. Features being my commands and queries. If you have not familiar with CQRS, it may be worth a look at some of my other posts to get some Context. Thin...
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Validating Commands
This post is how I have manged to handle validating commands and queries and belongs to a series about different aspects of applying CQRS Although these examples are demonstrating usage in commands,...
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Mediator Pattern with Hangfire
I’ve run into situations where I need to perform actions requested by the client that may take a bit of time. The length of time could be variable and I don’t want to have the client waiting for a...
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Background Commands with MediatR and Hangfire
I’ve been using MediatR and Hangfire independently for awhile. I’ve previously posted one solution on how you could use send Commands with MediatR and Hangfire. The solution I had come up with in that...
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