Read Model / Projection Generator

Creates Read Model infrastructure for CQRS read side with optimized query models.

When to Use

Scenario	Example
CQRS read side	Separate query models
Denormalized views	Dashboard aggregates
Complex queries	Multi-entity joins
Event-driven updates	Event projections

Component Characteristics

Read Model

• Optimized for queries
• Denormalized data
• Eventually consistent
• No business logic

Projection

• Builds read models from events
• Handles event streams
• Maintains synchronization
• Idempotent processing

Repository

• Query-focused methods
• Returns read models
• No write operations

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Generation Process

Step 1: Generate Domain Read Model

Path: src/Domain/{BoundedContext}/ReadModel/

1. {Name}ReadModel.php — Immutable read model with fromArray/toArray
2. {Name}ReadModelRepositoryInterface.php — Query-focused repository interface

Step 2: Generate Application Projection

Path: src/Application/{BoundedContext}/Projection/

1. {Name}ProjectionInterface.php — Projection contract
2. {Name}Projection.php — Event handlers building read model

Step 3: Generate Infrastructure

Path: src/Infrastructure/{BoundedContext}/

1. Projection/{Name}Store.php — Store for insert/update/upsert
2. ReadModel/Doctrine{Name}Repository.php — Repository implementation

Step 4: Generate Tests

1. {Name}ReadModelTest.php — Read model serialization tests
2. {Name}ProjectionTest.php — Projection event handling tests

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File Placement

Component	Path
Read Model	src/Domain/{BoundedContext}/ReadModel/
Repository Interface	src/Domain/{BoundedContext}/ReadModel/
Projection Interface	src/Application/{BoundedContext}/Projection/
Projection	src/Application/{BoundedContext}/Projection/
Store	src/Infrastructure/{BoundedContext}/Projection/
Repository Impl	src/Infrastructure/{BoundedContext}/ReadModel/
Unit Tests	tests/Unit/

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Naming Conventions

Component	Pattern	Example
Read Model	{Name}ReadModel	OrderSummaryReadModel
Repository Interface	{Name}ReadModelRepositoryInterface	OrderSummaryReadModelRepositoryInterface
Projection Interface	{Name}ProjectionInterface	OrderSummaryProjectionInterface
Projection	{Name}Projection	OrderSummaryProjection
Store	{Name}Store	OrderSummaryStore
Test	{ClassName}Test	OrderSummaryProjectionTest

---

Quick Template Reference

Read Model

final readonly class {Name}ReadModel
{
    public function __construct(
        public string $id,
        // ... denormalized properties
        public \DateTimeImmutable $createdAt,
        public \DateTimeImmutable $updatedAt
    ) {}

    public static function fromArray(array $data): self;
    public function toArray(): array;
}

Projection

final class {Name}Projection implements {Name}ProjectionInterface
{
    public function project(DomainEventInterface $event): void
    {
        match ($event::class) {
            OrderCreated::class => $this->whenOrderCreated($event),
            OrderShipped::class => $this->whenOrderShipped($event),
            default => null,
        };
    }

    public function reset(): void;
    public function subscribedEvents(): array;
}

---

Usage Example

// Query read model
$orders = $orderSummaryRepository->findByCustomerId($customerId);

// Project event
$projection->project($orderCreatedEvent);

// Reset projection for rebuild
$projection->reset();

---

Database Schema

CREATE TABLE order_summaries (
    id VARCHAR(36) PRIMARY KEY,
    order_number VARCHAR(50) NOT NULL UNIQUE,
    customer_id VARCHAR(36) NOT NULL,
    customer_name VARCHAR(255) NOT NULL,
    status VARCHAR(50) NOT NULL,
    total_cents BIGINT NOT NULL,
    created_at TIMESTAMP NOT NULL,
    updated_at TIMESTAMP NOT NULL,

    INDEX idx_customer (customer_id),
    INDEX idx_status (status)
);

---

Anti-patterns to Avoid

Anti-pattern	Problem	Solution
Business Logic	Read model has behavior	Keep data-only
Write Operations	Modifying read models	Use projections only
Non-idempotent	Re-projection breaks data	Idempotent event handling
Missing Reset	Can't rebuild	Add reset() method
Tight Coupling	Projection depends on domain	Use events only

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References

For complete PHP templates and examples, see:

• references/templates.md — Read model, projection, store templates
• references/examples.md — OrderSummary example and tests
• references/event-sourcing-projections.md — Event replay projections, versioning, checkpoint tracking, async workers