实体框架代码优先-相同类型的2个实体

Question

我试图在实体中映射2个相同类型的属性，并得到此错误：

An exception was thrown while executing a resolve operation. See the InnerException for details. ---> Introducing FOREIGN KEY constraint 'FK_dbo.Client_dbo.Messagebox_OutboxId' on table 'Client' may cause cycles or multiple cascade paths. Specify ON DELETE NO ACTION or ON UPDATE NO ACTION, or modify other FOREIGN KEY constraints.

无法创建约束。 请参阅先前的错误。 （有关详细信息，请参见内部异常。）

我知道这个错误与我拥有2个相同类型的道具有关。

如何使用代码优先+ EF Fluent API来完成？

方案：每个Client都有Inbox和Outbox ，它们都是Messagebox

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

public class Client : BaseEntity
{
    /// <summary>
    /// Gets or sets Client Alias
    /// </summary>
    public string Alias { get; set; }

    /// <summary>
    /// Gets or sets value indicating if the client was deleted
    /// </summary>
    public bool Deleted { get; set; }

    /// <summary>
    /// Gets or sets client's inbox
    /// </summary>
    public virtual Messagebox Inbox { get; set; }

    /// <summary>
    /// Gets or sets inbox Id
    /// </summary>
    public int InboxId { get; set; }

    /// <summary>
    /// Gets or sets client's outbox
    /// </summary>
    public virtual Messagebox Outbox { get; set; }

    /// <summary>
    /// Gets or sets outbox Id
    /// </summary>
    public int OutboxId { get; set; }
}

public class Messagebox : BaseEntity
{
    public int ClientId { get; set; }

    /// <summary>
    /// Gets or sets the messagebox client
    /// </summary>
    public virtual Client Client { get; set; }
}

Answer 1

此问题与使用两个具有相同名称的专家无关。 它与不愿创建表之间循环的约束的sql数据库有关。

您可以使用以下流畅的API来克服这一问题（请根据需要进行调整）

modelBuilder.Entity<Leaves>().HasRequired(l => l.Applicant)
                            .WithMany(bp => bp.LeavesToApply)
                            .HasForeignKey(l => l.ApplicantId)
                            .WillCascadeOnDelete(false);
modelBuilder.Entity<Leaves>().HasOptional(t => t.Approver)
                             .WithMany(bp => bp.LeavesToApprove)
                             .HasForeignKey(u => u.ApproverId)
                             .WillCascadeOnDelete(false);

问题是您必须转向Cascade。 并手动删除事物或删除循环。