c# - 是否可以在没有外键的情况下设置导航属性？

Question

是否可以有两个(或更多)相同类型的导航属性？

我的模型看起来像这样......

public class Agreement
{
    public int Id { get; set; }
    public Guid? BuyerId { get; set; }
    public Guid? SellerId { get; set; }

    public AgreementInfo ByerAgreementInfo { get; set; }
    public AgreementInfo SellerAgreementInfo { get; set; }
}

public class AgreementInfo
{
    // PK is AgreementId and OwnerActorId combined.
    public int AgreementId { get; set; }
    public Guid OwnerActorId { get; set; }
    public string Name { get; set; }
}

...我正在尝试通过匹配 AgreementId 和 ByerId/SellerId 来包含导航属性...

modelBuilder.Entity<Agreement>().HasOne(x => x.ByerAgreementInfo).WithOne().HasForeignKey<Agreement>(x => new {x.Id, x.ProviderId});
modelBuilder.Entity<Agreement>().HasOne(x => x.SellerAgreementInfo).WithOne().HasForeignKey<Agreement>(x => new { x.Id, x.RequesterId });

... but this results in a circural dependecy.

有没有办法不使用外键就包含这些属性？或者是否有另一种解决方案(除了向信息表添加一个 id 列)允许我将信息表行用作协议(protocol)类中的导航属性？

Answer 1

... but this results in a circural dependecy

是的!它会。要克服这个问题，您必须在 Fluent API 配置中指定 .OnDelete(DeleteBehavior.Restrict);，如下所示，但首先您必须编写您的协议(protocol) 模型类也如下:

public class Agreement
{
    public int Id { get; set; }
    public Guid? BuyerId { get; set; }
    public Guid? SellerId { get; set; }

    public int AgreementIdForBuyer { get; set; }
    public Guid OwnerActorIdForBuyer { get; set; }

    public int AgreementIdForSeller { get; set; }
    public Guid OwnerActorIdForSeller { get; set; }

    public AgreementInfo ByerAgreementInfo { get; set; }
    public AgreementInfo SellerAgreementInfo { get; set; }
}

现在在 Fluent API 配置中:

modelBuilder.Entity<Agreement>()
    .HasOne(x => x.ByerAgreementInfo)
    .WithOne()
    .HasForeignKey<Agreement>(p => new {p.AgreementIdForBuyer, p.AgreementIdForBuyer})
    .OnDelete(DeleteBehavior.Restrict); // <-- Here it is

modelBuilder.Entity<Agreement>()
    .HasOne(x => x.SellerAgreementInfo)
    .WithOne()
    .HasForeignKey<Agreement>(p => new {p.AgreementIdForSeller, p.OwnerActorIdForSeller})
    .OnDelete(DeleteBehavior.Restrict); // <-- Here it is