Start here. This is the direct spoken answer to practice first.
Why this question matters
Explain read models for complex API screens with practical .NET data-access examples and production trade-offs. It matters in real backend work because query shape, indexes, transactions, locking, and data volume can turn harmless-looking code into a production bottleneck. The practical angle is read models for complex API screens, EF Core/SQL behavior, API boundaries, production risks, and practical debugging or design judgment, tied to a concrete production decision.
A read model is a data shape optimized for reading a specific view or use case. I would consider it when the API screen needs complex joins, aggregates, or data from multiple sources and the live query becomes slow or fragile. The read model can be built from events, background jobs, or scheduled refreshes. It trades freshness for performance and simpler reads.