protected override void OnModelCreating(ModelBuilder modelBuilder) { modelBuilder.Entity <Auction>() .HasOne(auction => auction.AuctionDetail) .WithOne(auctionDetail => auctionDetail.Auction) .HasForeignKey <AuctionDetail>(auctionDetail => auctionDetail.AuctionId); // Seed data. DataSeeder seeder = new DataSeeder(); List <Make> makes = seeder.GenerateCarMakes(); modelBuilder.Entity <Make>().HasData(makes); List <Model> models = seeder.GenerateCarModels(); modelBuilder.Entity <Model>().HasData(models); List <Trim> trims = seeder.GenerateCarTrims(); modelBuilder.Entity <Trim>().HasData(trims); }