projection-patterns

Create projections and read models from event streams for CQRS architectures.

Updated Jul 7, 2026
One-click install
npx skills add https://github.com/voidrot/agents --skill projection-patterns-voidrot
Or copy as Structured Prompt for Agent
Please help me install this Agent Skill.
Skill: projection-patterns
Source: https://github.com/voidrot/agents/tree/main/skills/database/projection-patterns
Command: npx skills add https://github.com/voidrot/agents --skill projection-patterns-voidrot

SYSTEM DOCUMENTATION & REQUIREMENTS

💡 This Skill includes scripts (resource) and references (resource) components.

What problem does it solve?

This Skill assists in constructing efficient and reliable projections, materialized views, and search indexes from event streams, optimizing the design of read models and CQRS/event-sourced systems.

Core Features & Use Cases

  • Projection Patterns: Provides templates and examples for various projection types such as inline, live, catch-up, and persistent projections.
  • Use Case: Ideal for engineers building event-sourced applications and require a guide for designing projections for data aggregation, real-time analysis, or rebuilding from historical events.

Quick Start

Start with the requirements for your query or read model. Then, select the projection mode based on consistency or scale needs. Apply this skill to implement projection logic safely, handle idempotency, and store checkpoints.

Frequently Asked Questions about projection-patterns

High-intent search queries and answers about installing and using this skill.

FAQPage Schema
How do I build materialized views and read models from event streams?

You can build materialized views and read models from event streams by applying projection patterns that handle various projection types, safely implement projection logic, and store checkpoints for reliable data aggregation.

What projection patterns are available for event-sourced systems?

Projection patterns for event-sourced systems include inline, live, catch-up, and persistent projections. These patterns help manage data aggregation, real-time analysis, and rebuilding read models from historical events.

How do I handle idempotency and checkpointing when creating projections?

To handle idempotency and checkpointing when creating projections, apply specific projection logic patterns designed to safely process event streams and store checkpoints, preventing duplicate data updates during replay mechanisms.

When do I need projections for CQRS architectures?

You need projections for CQRS architectures when building event-sourced applications that require optimized read models, search indexes, or dashboards, and need a guide for designing projections for data aggregation or real-time analysis.

What is the best way to rebuild read models from historical events?

The best way to rebuild read models from historical events is using catch-up or persistent projection patterns, which support replay mechanisms and handle idempotency to ensure accurate data reconstruction.

Can I use this approach to create search indexes and dashboards?

Yes, you can use these projection patterns to create search indexes and dashboards. The approach focuses on generating materialized views and read models from event streams for real-time analysis and data aggregation.