Today we will see what is the CQRS – Command query responsibility segregator Design Pattern is.

Previously we saw about What is Microservice? and the principles followed while developing MSA and the available design patterns.

Command query responsibility segregator (CQRS) design pattern?

CQRS stands for Command Query responsibility segregator, a design pattern that separates the read and update operations for data.

In traditional architecture, the same data mode is used to query and update the data in a database, This is how the CRUD operations work. With CQRS the read and update operations are separated into two parts, Command and Query.

The command part will handle all the CREATE, UPDATE, DELETE requests, while the Query part will handle all the READ (Materialize view) requests.

 Advantages of CQRS:

• Performance
• Scalability
• Improves Security
• It also prevents update commends from causing merge conflicts at the domain level

Example:

 Consider we have Video Services, One for Uploading (Write Operation) and another for viewing (Read Operation).

Where Uploading will perform Create, Update, Delete operations. And the other service on viewing will perform a Select operation to read the videos and their metadata.