How do you seed initial data using migrations / EF Core configuration?

Short answer: Use the HasData() method in OnModelCreating(): modelBuilder.Entity<User>().HasData( new User { Id = 1, Name = "Admin" } ); Data is inserted automatically during Update-Database. Changes to seed data require a new migration.

Real-world example (ShopNest)

When ShopNest adds a DiscountCode column, you create a migration, review the SQL, then apply it on staging before production.

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.