Understanding the CQRS Design Pattern: Separating Commands and Queries for Scalable Systems
Modern applications are increasingly expected to handle massive data volumes, evolving business logic, and performance-sensitive workloads. While traditional CRUD-based architectures (Create, Read, Update, Delete) have served well for decades, they can struggle under complex real-world demands — especially when read and write workloads grow at different rates. This is where CQRS (Command Query Responsibility Segregation) comes into play. What Is CQRS? CQRS, coined by Greg Young , is a design pattern that separates the responsibilities of reading and writing data into distinct models: Command side (Write model): Handles actions that change state, such as creating, updating, or deleting records. Query side (Read model): Focuses on efficiently retrieving data, often optimized for fast reads or specific query patterns. Instead of a single model handling both operations, CQRS gives each responsibility its own tailored design, allowing for cleaner separation of c...