Projection Patterns

1---
2name: projection-patterns
3description: Build read models and projections from event streams. Use when implementing CQRS read sides, building materialized views, or optimizing query performance in event-sourced systems.
4---
5 
6# Projection Patterns
7 
8Comprehensive guide to building projections and read models for event-sourced systems.
9 
10## Use this skill when
11 
12- Building CQRS read models
13- Creating materialized views from events
14- Optimizing query performance
15- Implementing real-time dashboards
16- Building search indexes from events
17- Aggregating data across streams
18 
19## Do not use this skill when
20 
21- The task is unrelated to projection patterns
22- You need a different domain or tool outside this scope
23 
24## Instructions
25 
26- Clarify goals, constraints, and required inputs.
27- Apply relevant best practices and validate outcomes.
28- Provide actionable steps and verification.
29- If detailed examples are required, open `resources/implementation-playbook.md`.
30 
31## Resources
32 
33- `resources/implementation-playbook.md` for detailed patterns and examples.
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