Kas saaksite selgitada CQRS mudeli tööpõhimõtet ja peamisi omadusi?

CQRS (Command Query Responsibility Segregation) is an architectural pattern that separates the operations that change state (commands) from the operations that read data (queries) into different models.

Principle of operation:

• Commands are operations that modify the system's state. They are processed separately and can have complex validation logic and business rules.
• Queries are operations that read data without changing the state. They are optimized for fast and efficient information retrieval.

Main features:

• Separating models allows optimizing each for its tasks: the command model can be complex and support business logic, while the query model is simple and fast.
• Often a separate storage or projection is used for queries, increasing read performance.
• Improves scalability, as read and write operations can be scaled independently.
• Can complicate architecture due to the need for synchronization between models.

Example: In an order management system:

• The CreateOrder command changes the state by creating an order.
• The GetOrderDetails query returns information about the order using an optimized read model.

CQRS is often combined with Event Sourcing, where state changes are stored as events, simplifying synchronization and state recovery.