How to use compiled queries for performance?

Short answer: Precompile frequently used queries to improve performance: private static readonly Func<MyDbContext, int, Product> _getProductById = EF.CompileQuery((MyDbContext ctx, int id) => ctx.Products.First(p => p.Id == id)); // Usage: var product = _getProductById(context, 5);

Real-world example (ShopNest)

ShopNest’s order service uses EF Core to save an Order and its line items in one SaveChangesAsync() call inside a transaction.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.