请仔细阅读这个问题:Create code first, many to many, with additional fields in association table组合键和分离身份密钥
这里是OP的场景:
public class Member
{
public int MemberID { get; set; }
public string FirstName { get; set; }
public string LastName { get; set; }
public virtual ICollection<Comment> Comments { get; set; }
}
public class Comment
{
public int CommentID { get; set; }
public string Message { get; set; }
public virtual ICollection<Member> Members { get; set; }
}
public class MemberComment
{
public int MemberID { get; set; }
public int CommentID { get; set; }
public int Something { get; set; }
public string SomethingElse { get; set; }
}
接受的答案是:
public class MemberComment
{
[Key, Column(Order = 0)]
public int MemberID { get; set; }
[Key, Column(Order = 1)]
public int CommentID { get; set; }
public virtual Member Member { get; set; }
public virtual Comment Comment { get; set; }
public int Something { get; set; }
public string SomethingElse { get; set; }
}
现在,我的问题是:如果我想添加另一个身份字段,如Guid或AutoInc int,例如:
public int MemberCommentID { get; set; }
我不是在讨论这是更好的方法还是没有,我想知道我该怎么做?
我在想这样的事情
public class MemberComment
{
[Key, Column(Order = 0)]
public int MemberCommentID { get; set; }
[Key, Column(Order = 1)]
public int MemberID { get; set; }
[Key, Column(Order = 2)]
public int CommentID { get; set; }
public virtual Member Member { get; set; }
public virtual Comment Comment { get; set; }
public int Something { get; set; }
public string SomethingElse { get; set; }
}
但随后EF将(我认为)使用的关键,权当是MemberCommentID的3场是孤独的1个键,MEMBERID + CommentID是另一个关键。
为什么它没有强制执行关键的MemberID + CommentID,如果我尝试用重复的MemberID + CommentID添加一个新的MemberComment,EF不会抛出任何错误..:/ –
是的,我知道它是完美的......痛苦工作和维护现有数据库:/ –
@ClickOk因此,它是[code-first-from-database](https://msdn.microsoft.com/en-us/library/jj200620.aspx),而不是代码优先因为它在你的问题中被标记,或者我错过了什么? –