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CQRS Journey

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July 2012

Exploring CQRS and Event Sourcing

The project is focused on building highly scalable, highly available and maintainable applications with the Command & Query Responsibility Segregation and the Event Sourcing patterns.

The project was positioned as a learning journey. This guidance is designed to help you get started with the CQRS pattern and event sourcing. It is not intended to be the definitive guide to the CQRS pattern and event sourcing. Instead, it's a journal that describes the experiences of a development team with no prior CQRS proficiency in building, deploying (to Microsoft Azure), and maintaining a sample real-world complex enterprise system as a reference implementation (RI) to showcase various CQRS and ES concepts & techniques. The development team did not work in isolation; we actively sought input from industry experts and from a wider group of advisors to ensure that the guidance is both detailed and practical.

The CQRS pattern and event sourcing are not mere simplistic solutions to the problems associated with large-scale, distributed systems. By providing you with both a working application and written guidance, we expect you'll be well prepared to embark on your own CQRS journey.

This written guidance is itself split into three distinct sections that you can read independently: a description of the journey we took as we learned about CQRS, a collection of CQRS reference materials, and a collection of case studies that describe the experiences other teams have had with the CQRS pattern. The map below illustrates the relationship between the first two sections and our main milestones.

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CQRS Journey - Reference Implementation Evolution

CQRS Journey – Reference Implementation Evolution

Release Notes

Release Notes, Migration Notes, Known Issues

Deployed Live Reference Implementation

Registrant View, Business Customer View


What other readers are saying about the guide

Foreword by Greg Young


A CQRS journey

CQRS reference

Tales from the trenches


A Journey into CQRS (Channel9)

Feedback and Issue Reporting


©2012 Microsoft. All rights reserved. Certain content used with permission from contributors. Licensed under the Apache License, Version 2.0

Authors and Contributors

This guide was produced by the following individuals:

  • Program and Product Management: Grigori Melnik (Microsoft Corporation)
  • Development: Julian Dominguez (Microsoft Corporation), Daniel Cazzulino and Fernando Simonazzi (Clarius Consulting)
  • Testing: Mani Subramanian (Microsoft Corporation), Hernan de Lahitte (Digit Factory), Rathi Velusamy (Infosys Technologies Ltd.)
  • Documentation: Dominic Betts (Content Master Ltd), Julian Dominguez, Grigori Melnik, and Mani Subramanian (Microsoft Corporation), and Fernando Simonazzi (Clarius Consulting)
  • Graphic design: Alexander Ustinov and Anton Rusecki (JetStyle)
  • Editing and production: RoAnn Corbisier and Nelly Delgado (Microsoft Corporation) and Nancy Michell (Content Master Ltd.).

We want to thank the DDD/CQRS community members who have accompanied us on this journey and patiently reviewed our early content and drafts. Suggestions, insights, critiques, challenges, and reviews by our advisory board members are appreciated. Among those, we would like to highlight the exceptional contributions of Greg Young, Kelly Sommers, Clemens Vasters, Glenn Block, Udi Dahan, Adam Dymitruk, Bruno Terkaly, Cesar De la Torre Llorente, Ricardo Villalobos, Christopher Bennage, Eugenio Pace, Josh Elster, Mark Seemann, Matias Woloski, Peter Ritchie, Bill Wilder, and Tim Shakarian.

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