cqrs-implementation

# CQRS Implementation

Comprehensive guide to implementing CQRS (Command Query Responsibility Segregation) patterns.

## When to Use This Skill

- Separating read and write concerns
- Scaling reads independently from writes
- Building event-sourced systems
- Optimizing complex query scenarios
- Different read/write data models needed
- High-performance reporting requirements

## Core Concepts

### 1. CQRS Architecture

```
                    ┌─────────────┐
                    │   Client    │
                    └──────┬──────┘
                           │
              ┌────────────┴────────────┐
              │                         │
              ▼                         ▼
       ┌─────────────┐          ┌─────────────┐
       │  Commands   │          │   Queries   │
       │    API      │          │    API      │
       └──────┬──────┘          └──────┬──────┘
              │                         │
              ▼                         ▼
       ┌─────────────┐          ┌─────────────┐
       │  Command    │          │   Query     │
       │  Handlers   │          │  Handlers   │
       └──────┬──────┘          └──────┬──────┘
              │                         │
              ▼                         ▼
       ┌─────────────┐          ┌─────────────┐
       │   Write     │─────────►│    Read     │
       │   Model     │  Events  │   Model     │
       └─────────────┘          └─────────────┘
```

### 2. Key Components

| Component           | Responsibility                  |
| ------------------- | ------------------------------- |
| **Command**         | Intent to change state          |
| **Command Handler** | Validates and executes commands |
| **Event**           | Record of state change          |
| **Query**           | Request for data                |
| **Query Handler**   | Retrieves data from read model  |
| **Projector**       | Updates read model from events  |

## Templates

### Template 1: Command Infrastructure

```python
from abc