Question

为什么有UserProgramRefProgramCharacteristics.RefProgramCharacteristicsId字段???应该只有2个字段而不是3.对吧？下面是创建多对多表

所需的3个类和OnModelCreating

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

    public string ProgramCharacteristic { get; set; }

     public List<UserProgramRefProgramCharacteristic> UserProgramRefProgramCharacteristics { get; set; }

    // public ICollection<UserProgram> userPrograms { get; } = new List<UserProgram>();

   // public virtual ICollection<UserProgram> UserPrograms { get; set; }
}


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

    //UserProgramSaved
    public bool MyList { get; set; }
    public float MyPriorityRating { get; set; }
    public int Similarity { get; set; }
    public bool Compare { get; set; }

    //UserProgramSimilarity
    public int OverallSimilarityScore { get; set; }
    public int DeltaProfileElement1_WorkExp { get; set; }
    public int DeltaProfileElement2_VolExp { get; set; }
    public int DeltaProfileElement3_ResExp { get; set; }
    public int DeltaProfileElement4_Pubs { get; set; }
    public int DeltaProfileElement5_Step1 { get; set; }
    public int DeltaProfileElement6_Step2ck { get; set; }
    public int DeltaProfileElement7_Aoa { get; set; }
    public int DeltaProfileElement8_Nspecialties { get; set; }
    public int DeltaProfileElement9_PercentApps { get; set; }

    //UserComparisonSaved
    //  public RefProgramCharacteristic RefProgramCharacteristic { get; set; }
    public string RefProgramCharacteristicList { get; set; }


    public string ApplicationUserId { get; set; }
    public ApplicationUser ApplicationUser { get; set; }


    public int MedicalProgramId { get; set; }
    public RefProgramDetailData MedicalProgram { get; set; }


     public List<UserProgramRefProgramCharacteristic> UserProgramRefProgramCharacteristics { get; set; }

   // public ICollection<RefProgramCharacteristic> RefProgramCharacteristics { get; } = new List<RefProgramCharacteristic>();

   // public virtual ICollection<RefProgramCharacteristic> RefProgramCharacteristics { get; set; }


}


   public class UserProgramRefProgramCharacteristic
{
  //  public int Id { get; set; }

    public int UserProgramId { get; set; }
    public UserProgram UserProgram { get; set; }


    public int RefProgramCharacteristicsId { get; set; }
    public RefProgramCharacteristic RefProgramCharacteristic { get; set; }
}


  protected override void OnModelCreating(ModelBuilder builder)
    {
        builder.Entity<UserProgramRefProgramCharacteristic>()
            .HasKey(t => new { t.UserProgramId, t.RefProgramCharacteristicsId });

        base.OnModelCreating(builder);
    }

Answer 1

为什么有UserProgramRefProgramCharacteristics.RefProgramCharacteristicsId字段？

因为您告诉EF Core在此创建此类字段：

public int RefProgramCharacteristicsId { get; set; }
//                                 ^

导航属性名为RefProgramCharacteristic（无s）。 by EF Core conventions：

如果从属实体包含名为＆lt;主键属性名称＆gt; ，＆lt;导航属性名称＆gt;＆lt;主键属性名称＆gt; 或＆lt;主体实体名称＆gt;＆lt;主键属性名称＆gt; 然后将其配置为外键。

RefProgramCharacteristicsId与这些规则中的任何一个都不匹配，因此EF Core会创建一个默认名称为RefProgramCharacteristicId的影子FK属性。

将属性重命名为RefProgramCharacteristicId（最佳），或使用ForeignKey数据注释显式映射：

[ForeignKey(nameof(RefProgramCharacteristicsId))]
public RefProgramCharacteristic RefProgramCharacteristic { get; set; }

或

[ForeignKey(nameof(RefProgramCharacteristic))]
public int RefProgramCharacteristicsId { get; set; }

或使用HasForeignKey流畅的API：

builder.Entity<UserProgramRefProgramCharacteristic>()
    .HasOne(e => e.RefProgramCharacteristic)
    .WithMany(e => e.UserProgramRefProgramCharacteristics)
    .HasForeignKey(e => e.RefProgramCharacteristicsId);

EF核心并创建了多对多的表。创建额外的字段。为什么？

1 个答案: