EF Core Code-First Migration 级联删除问题

Question

我已经开始处理一个项目的后端部分，目前，我正在尝试使用EF Core Code-First生成数据库，但是当我尝试运行迁移时遇到了一个问题（与级联删除）。

首先，我将在数据库和我在 C# 中创建的类的ERD下方附加：

对应的分类是：

账户.cs

public class Account
{
   public int Id { get; set; }
   public string Email { get; set; }
   public string ExternalAccountId { get; set; }

   public int CustomerId { get; set; }
   public Customer Customer { get; set; }
}

BillingAddress.cs

public class BillingAddress
{
   public int Id { get; set; }
   public string Address { get; set; }

   public int CustomerId { get; set; }
   public Customer Customer { get; set; }

   public List<Payment> Payments { get; set; }
}

BillingDetail.cs

public class BillingDetail
{
   public int Id { get; set; }
   public int CreditCardNumber { get; set; }
   public DateTime ExpirationDate { get; set; }
   public short Cvv { get; set; }

   public int CustomerId { get; set; }
   public Customer Customer { get; set; }

   public List<Payment> Payments { get; set; }
}

客户.cs

public class Customer
{
   public int Id { get; set; }
   public string FirstName { get; set; }
   public string LastName { get; set; }
   public string PhoneNumber { get; set; }
   public int Cnp { get; set; }

   public Account Account { get; set; }

   public List<BillingDetail> BillingDetails { get; set; }

   public List<BillingAddress> BillingAddresses { get; set; }

   public List<Rental> Rentals { get; set; }
}

Payment.cs

public class Payment
{
    public int Id { get; set; }

    public int RentalId { get; set; }
    public Rental Rental { get; set; }

    public int BillingDetailId { get; set; }
    public BillingDetail BillingDetail { get; set; }

    public int BillingAddressId { get; set; }
    public BillingAddress BillingAddress { get; set; }
}

出租.cs

public class Rental
{
   public int Id { get; set; }
   public DateTime PickupDate { get; set; }
   public DateTime DropoffDate { get; set; }

   public int CustomerId { get; set; }
   public Customer Customer { get; set; }

   public List<Payment> Payments { get; set; }

   public List<RentalVehicle> RentalVehicles { get; set; }
}

RentalVehicle.cs

public class RentalVehicle
{
   public int Id { get; set; }

   public int RentalId { get; set; }
   public Rental Rental { get; set; }

   public int VehicleId { get; set; }
   public Vehicle Vehicle { get; set; }
}

车辆.cs

public class Vehicle
{
   public int Id { get; set; }
   public string Model { get; set; }
   public string Brand { get; set; }
   public string Color { get; set; }
   public short ManufactureYear { get; set; }
   public string Vin { get; set; }
   public int Mileage { get; set; }
   public short Horsepower { get; set; }
   public string GearBox { get; set; }
   public byte EngineSize { get; set; }
   public float Price { get; set; }
   public byte NoDoors { get; set; }

   public List<RentalVehicle> RentalVehicles { get; set; }
}

我已经生成了迁移，当我尝试运行它时，我收到如下错误：

Introducing FOREIGN KEY constraint 'FK_Payments_BillingDetails_BillingDetailId' on table 'Payments' may cause cycles or multiple cascade paths. Specify ON DELETE NO ACTION or ON UPDATE NO ACTION, or modify other FOREIGN KEY constraints.

我已经发现了一些固定的迁移ReferentialAction.NoAction为onDelete更换ReferentialAction.Cascade，但我不知道如果我真的应该这样做，以及它如何将在长期影响这个东西我的应用程序。

我到底应该怎么做才能解决这个问题，这是最佳实践？

Answer 1

如果您正在编辑迁移，您可能需要更改实体的配置。

例子：

public class PaymentsConfiguration : IEntityTypeConfiguration<Payments>
    {
        public override void Configure(EntityTypeBuilder<Payments> builder)
        {
            builder.HasOne(x => x.BillingDetail).WithMany().OnDelete(DeleteBehavior.Restrict);
            builder.HasOne(x => x. BillingAddress).WithMany().OnDelete(DeleteBehavior.Restrict); //maybe you need to do this too
            builder.HasOne(x => x. Rental).WithMany().OnDelete(DeleteBehavior.Restrict); //maybe you need to do this too
        }
    }

我会查看以下有关配置的文档/教程：

• 配置
• 将 Fluent API 配置移动到实体框架中的单独类
  • 这是EF6，但它的想法相同
• EF Core 级联删除

在我过去完成的项目中，一些主要开发人员向我建议不要级联删除。 尽管它很方便，但您应该注意要删除的数据……EF Core 很棒，但有时它会将您默认为某些 DBA 不会满意的行为。