Cqrs Pattern Example

{
  "title": "CQRS Architectural Pattern - Example Documentation",
  "description": "Example of documenting the CQRS (Command Query Responsibility Segregation) architectural pattern",
  "data": {
    "id": "cqrs",
    "name": "CQRS (Command Query Responsibility Segregation)",
    "category": "CQRS",
    "description": "CQRS separates read (query) and write (command) operations into distinct models. The command side handles state-changing operations, while the query side is optimized for reads. This allows each side to scale, optimize, and evolve independently.",
    "aliases": ["Command Query Responsibility Segregation"],
    "components": [
      {
        "name": "Command Model",
        "description": "Handles state-changing write operations",
        "responsibilities": [
          "Process commands that change system state",
          "Validate business rules",
          "Emit domain events",
          "Update the write data store"
        ]
      },
      {
        "name": "Query Model",
        "description": "Handles read operations returning data",
        "responsibilities": [
          "Answer queries with read-optimized views",
          "Maintain denormalized read projections",
          "Subscribe to domain events to keep views current"
        ]
      },
      {
        "name": "Command Bus",
        "description": "Routes commands to appropriate command handlers",
        "responsibilities": [
          "Dispatch commands to handlers",
          "Provide middleware for validation and logging"
        ]
      },
      {
        "name": "Event Store",
        "description": "Persists domain events for event sourcing integration",
        "responsibilities": [
          "Append-only storage of domain events",
          "Event replay for rebuilding state"
        ]
      }
    ],
    "useCases": [
      "High-traffic applications where reads vastly outnumber writes",
      "Complex domain models where read and write concerns differ significantly",
      "Event-sourced systems requiring full audit trails",
      "Collaborative domains with complex concurrency requirements",
      "Microservices needing independent scaling of read and write sides"
    ],
    "benefits": [
      "Independent scaling of read and write workloads",
      "Optimized read models for complex queries",
      "Improved security through separation of concern",
      "Enables event sourcing and full audit history",
      "Reduces contention on shared data models"
    ],
    "tradeoffs": [
      "Increased system complexity",
      "Eventual consistency between command and query sides",
      "Requires messaging infrastructure for event distribution",
      "More code to maintain (two models instead of one)",
      "Debugging becomes harder across the command/query boundary"
    ],
    "relatedPatterns": ["Event Sourcing", "Domain-Driven Design", "Saga", "Microservices"],
    "references": [
      {
        "title": "CQRS Pattern - Azure Architecture Center",
        "url": "https://learn.microsoft.com/en-us/azure/architecture/patterns/cqrs",
        "author": "Microsoft"
      },
      {
        "title": "CQRS Pattern - microservices.io",
        "url": "https://microservices.io/patterns/data/cqrs.html",
        "author": "Chris Richardson"
      }
    ]
  }
}