Book Image

Implementing Azure: Putting Modern DevOps to Use

By : Florian Klaffenbach, Oliver Michalski, Markus Klein, Mohamed Waly, Namit Tanasseri, Rahul Rai
Book Image

Implementing Azure: Putting Modern DevOps to Use

By: Florian Klaffenbach, Oliver Michalski, Markus Klein, Mohamed Waly, Namit Tanasseri, Rahul Rai

Overview of this book

This Learning Path helps you understand microservices architecture and leverage various services of Microsoft Azure Service Fabric to build, deploy, and maintain highly scalable enterprise-grade applications. You will learn to select an appropriate Azure backend structure for your solutions and work with its toolkit and managed apps to share your solutions with its service catalog. As you progress through the Learning Path, you will study Azure Cloud Services, Azure-managed Kubernetes, and Azure Container Services deployment techniques. To apply all that you’ve understood, you will build an end-to-end Azure system in scalable, decoupled tiers for an industrial bakery with three business domains. Toward the end of this Learning Path, you will build another scalable architecture using Azure Service Bus topics to send orders between decoupled business domains with scalable worker roles processing these orders. By the end of this Learning Path, you will be comfortable in using development, deployment, and maintenance processes to build robust cloud solutions on Azure. This Learning Path includes content from the following Packt products: • Learn Microsoft Azure by Mohamed Wali • Implementing Azure Solutions - Second Edition by Florian Klaffenbach, Oliver Michalski, Markus Klein • Microservices with Azure by Namit Tanasseri and Rahul Rai
Table of Contents (29 chapters)
Title Page
Copyright and Credits
About Packt
Contributors
Preface
Index

CQRS – Command Query Responsibility Segregation


Problem

State data in traditional applications is represented through a set of entities. The entities are stored in a single data repository against which two types of operations can take place.

  • Commands: Operations that modify state
  • Queries: Operations that read state

An operation cannot both update state and return data. This distinction of operations helps simplify understanding the system. The segregation of operations into commands and queries is called the Command Query Separation (CQS) pattern. The CQS pattern requires the commands to have void return type and the queries to be idempotent.

If a relational database such as SQL Server is used for storing state, the entities may represent a subset of rows in one or more tables in the database.

A common problem that arises in these systems is that both the commands and queries are applied to the same set of entities. For example, to update the contact details of a customer in a traditional e-commerce...