protected override void OnModelCreating(ModelBuilder modelBuilder) { modelBuilder.Entity <AvailableTickets>().HasData(Seed.AvailableTickets()); var reservedTicketEntity = modelBuilder.Entity <ReservedTicket>(); var reservationEntity = modelBuilder.Entity <Reservation>(); reservedTicketEntity .HasOne <Reservation>() .WithMany(r => r.ReservedTickets) .IsRequired() .HasForeignKey(so => so.ReservationId) .OnDelete(DeleteBehavior.Cascade); var orderedTicketEntity = modelBuilder.Entity <OrderedTicket>(); var orderEntity = modelBuilder.Entity <Order>(); orderedTicketEntity .HasOne <Order>() .WithMany(r => r.OrderedTickets) .IsRequired() .HasForeignKey(so => so.OrderId) .OnDelete(DeleteBehavior.Cascade); base.OnModelCreating(modelBuilder); }