为什么我得到一个额外的外键列与实体框架代码第一外键属性？ [英] Why am I getting an extra foreign key column with Entity Framework Code First Foreign Key Attributes?

问题描述

我的课程看起来像这样

  public class Status 
 {
 [Key] 
 public int StatusID {get;组; } 
 public string Name {get;组; } 
 public int MemberID {get;组; } 
 
 [ForeignKey（MemberID）] 
 public virtual Member Member {get;组; } 
 
 public int PosterID {get;组; } 
 
 [ForeignKey（PosterID）] 
 public virtual Member Poster {get;组; } 
 
 public virtual ICollection< StatusLike> StatusLikes {get;组; } 
 public virtual ICollection< StatusComment> StatusComments {get;组; 
} 
  

我的会员类看起来像这样

  public class Member 
 {
 [Key] 
 public int MemberID {get;组; } 
 public string FirstName {get;组; } 
 public string LastName {get;组; } 
 public string Bio {get;组; } 
 
 public virtual ICollection< MemberCourseTaken>会员中心组; } 
 public virtual ICollection< Status>状态{get;组; } 
 public virtual ICollection< Club> FoundedClubs {get;组; } 
 
 public string EmailAddress {get;组; } 
 public string Password {get;组; } 
 public string Phone {get;组; } 
 
 public int AccountSourceID {get;组; } 
 public AccountSource AccountSource {get;组; } 
 
 public int AddressID {get;组; } 
 public Address Address {get;组; } 
 public string ProfilePhoto {get;组; } 
 
 public int MemberRankID {get;组; } 
 public MemberRank MemberRank {get;组; } 
 public DateTime Created {get;组; } 
 public DateTime Modified {get;组; } 
} 
  

由于任何原因，创建的数据库表具有以下列

  StatusID 
名称
 MemberID 
 PosterID 
 Member_MemberID 
  

与 MemberID ， PosterID 和 Member_MemberID 是外键。

如何保持 Member_MemberID 被生成

解决方案

您的 Member_MemberID 由于 Member.Statuses 属性，因此创建了列。我可以想象，这不是你想要的。可能的成员和状态应该彼此独立存在，所以你需要一个连接表。

我不知道你是否已经使用了 OnModelCreating 覆盖DbContext，但这是更改成员和状态之间的映射的地方：

  protected覆盖void OnModelCreating（DbModelBuilder mb）
 {
 mb.Entity< Member>（）。HasMany（m => m.Statuses）.WithMany（）; 
} 
  

这将创建一个具有两个Id列作为外键的表MemberStatuses表。这是一种在关联的其他一侧没有导航属性来建立多对多关系的方法。 （我不认为你想在状态中的成员属性。

I recently came across this strange problem with Entity Framework Code First.

My class looks like this

public class Status
{
        [Key]
        public int StatusID { get; set; }     
        public string Name { get; set; }
        public int MemberID { get; set; }

        [ForeignKey("MemberID")]
        public virtual Member Member { get; set; }                

        public int PosterID { get; set; }

        [ForeignKey("PosterID")]
        public virtual Member Poster { get; set; }        

        public virtual ICollection<StatusLike> StatusLikes { get; set; }        
        public virtual ICollection<StatusComment> StatusComments { get; set; }
}

My Member class looks like this

 public class Member
    {
        [Key]
        public int MemberID { get; set; }
        public string FirstName { get; set; }
        public string LastName { get; set; }
        public string Bio { get; set; }

        public virtual ICollection<MemberCourseTaken> MemberCourseTakens { get; set; }
        public virtual ICollection<Status> Statuses { get; set; }
        public virtual ICollection<Club> FoundedClubs { get; set; }

        public string EmailAddress { get; set; }
        public string Password { get; set; }
        public string Phone { get; set; }

        public int AccountSourceID { get; set; }
        public AccountSource AccountSource { get; set; }

        public int AddressID { get; set; }
        public Address Address { get; set; }
        public string ProfilePhoto { get; set; }

        public int MemberRankID { get; set; }
        public MemberRank MemberRank { get; set; }
        public DateTime Created { get; set; }
        public DateTime Modified { get; set; }
    }

And for whatever reason the database table that is created has the following columns

StatusID
Name
MemberID
PosterID
Member_MemberID

with MemberID, PosterID, and Member_MemberID being foreign keys.

How can I keep Member_MemberID from being generated?

解决方案

Your Member_MemberID column is created because of the Member.Statuses property. I can imagine that this is not what you want. Probably members and statuses should exist independent of each other, so you need a junction table.

I don't know if you already use the OnModelCreating override of the DbContext, but that's the place to change the mapping between Member and Status:

protected override void OnModelCreating(DbModelBuilder mb)
{
    mb.Entity<Member>().HasMany(m => m.Statuses).WithMany();
}

This will create a table MemberStatuses table with the two Id columns as foreign keys. This is a way to model a many-to-many relationship without a navigation property on the "other" side of the association. (I don't think you want a Members property in Status).

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