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Would you care to expand on what "the whole point" of CQRS is, or how they missed it? You seem to imply that the existence or creation of a library to support

Would you care to expand on what "the whole point" of CQRS is, or how they missed it? You seem to imply that the existence or creation of a library to support the pattern is, in some sense, against the spirit of the pattern, which is a) not at all obvious to me, and b) seems like something you should expand upon if you're criticising the article and/or author for HN's civil dialogue guidelines.

osd 10y ago
This is a guess, but if I were to have a problem with the term CQRS Library, it is that the query and command sides of CQRS really shouldn't be linked in any way. CQRS is a methodology that stresses that decoupling above all else. If your the command and query portions of your CQRS tech stack both fall under a single library, that seems to go against the methodology.
realntl1 10y ago
I think CQRS is more commonly viewed as an architectural pattern, not a code pattern, despite many definitions floating out there on the internet that focus on command/query object patterns. See this post: http://udidahan.com/2009/12/09/clarified-cqrs/ http://udidahan.com/2009/12/09/clarified-cqrs/. If we view it as an architectural pattern, it becomes folly to think that CQRS can be distilled into a library.
- sb8244 10y ago
  > it becomes folly to think that CQRS can be distilled into a library Sincerely curious about this statement. I understand that CQRS is an architectural pattern, but couldn't a library implement that architecture and then provide ways for you to implement into that architecture? You don't get to pick the architecture nuances at that point, though.
  - karmajunkie 10y ago
    At its most basic level, CQRS is frankly too simple to take on a dependency as a cornerstone of a project. You can write a single base class that handles all of the responsibilities needed. Its NOT an architecture—its an architectural tool.
    - kellyleahy 10y ago
      Agreed. This is so true. I've never ended up with a "library" for doing this. At my previous employer we had three different CQRS-based systems and two of the three of them even had completely different implementations for 90% of the CQRS infrastructure. They are both successful implementations and there was no need to share that bit of the code, as the two teams doing things came to different conclusions on how they wanted to write their CQRS code. The only thing we shared was the event store and some of the minor things on top of the event store.
  - Terr_ 10y ago
    IMO it's a bit like talking about a "Facade Framework". Using facades to encapsulate multiple complex objects behind a simpler interface may be an important of your overall design, but even if you use them it a lot you probably don't need (or want) to build a "Facade Framework" that lets you instantly define new ones with a few lines of meta-code. Any code you make for reuse by other people is going to contain something more in order to have value to them. For example, "A Facade library for dealing with various cloud services". Relating it back to CRQS, compare "CQRS Framework" to "A CQRS framework for command-line applications" or "A CQRS framework for websites". The CQRS-ness is a quality that can't stand just on its own.

osd 10y ago

This is a guess, but if I were to have a problem with the term CQRS Library, it is that the query and command sides of CQRS really shouldn't be linked in any way. CQRS is a methodology that stresses that decoupling above all else. If your the command and query portions of your CQRS tech stack both fall under a single library, that seems to go against the methodology.

realntl1 10y ago

I think CQRS is more commonly viewed as an architectural pattern, not a code pattern, despite many definitions floating out there on the internet that focus on command/query object patterns. See this post: http://udidahan.com/2009/12/09/clarified-cqrs/ http://udidahan.com/2009/12/09/clarified-cqrs/. If we view it as an architectural pattern, it becomes folly to think that CQRS can be distilled into a library.

sb8244 10y ago
> it becomes folly to think that CQRS can be distilled into a library Sincerely curious about this statement. I understand that CQRS is an architectural pattern, but couldn't a library implement that architecture and then provide ways for you to implement into that architecture? You don't get to pick the architecture nuances at that point, though.
- karmajunkie 10y ago
  At its most basic level, CQRS is frankly too simple to take on a dependency as a cornerstone of a project. You can write a single base class that handles all of the responsibilities needed. Its NOT an architecture—its an architectural tool.
  - kellyleahy 10y ago
    Agreed. This is so true. I've never ended up with a "library" for doing this. At my previous employer we had three different CQRS-based systems and two of the three of them even had completely different implementations for 90% of the CQRS infrastructure. They are both successful implementations and there was no need to share that bit of the code, as the two teams doing things came to different conclusions on how they wanted to write their CQRS code. The only thing we shared was the event store and some of the minor things on top of the event store.
- Terr_ 10y ago
  IMO it's a bit like talking about a "Facade Framework". Using facades to encapsulate multiple complex objects behind a simpler interface may be an important of your overall design, but even if you use them it a lot you probably don't need (or want) to build a "Facade Framework" that lets you instantly define new ones with a few lines of meta-code. Any code you make for reuse by other people is going to contain something more in order to have value to them. For example, "A Facade library for dealing with various cloud services". Relating it back to CRQS, compare "CQRS Framework" to "A CQRS framework for command-line applications" or "A CQRS framework for websites". The CQRS-ness is a quality that can't stand just on its own.