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In the last few years there is a new paradigm rising in application architecture. It is called CQRS, Command Query Responsibility Segregation.

I had the opportunity to implement a first System with this paradigm and I would like to share my impressions:

In opposition to CRUD (Create Read Update Delete) Systems architectures it has the following advantages:

Reduction of Complexity: A CQRS System has a clearly separated Read and Write side thus programs are easer to write both in teams and alone.

High Testability: A CQRS System allows for easy configuration of any state your application should be for a test.
Unlike other Architectures there is inherently no dependency on the database to come into a state you need to test.

Real-time Collaboration: Users can manipulate shared Domainlogic and are instantly aware of the changes. Response to Changes is percieved as fast.

Easily Distributable: Messaging oriented middle-ware is an easy extension to the base concept of event drivenness.

No Object-Relational Mapping: Whatever OO-language you use: there is the Problem of Object-relational impedance mismatch ( http://en.wikipedia.org/wiki/Object-relational_impedance_mismatch). This is gone since all information is persisted in an event stream.

Inherent User insight: the center of the conceptual framework is the event which represents the fullfilment of a user Intent. It is easy to know what your user wanted to do with the system. This is not only UX insight but business performance indicators.

# Has anyone allready an opinion about the topic
# Do you find CQRS interesting? Can we deepen the argument?