Question

我有一个代码优先的MVC4 C＃应用程序，这两个模型

public class ClassRoom {
    public int ID { get; set; }
    public string ClassName { get; set; }
    public virtual ICollection<Pupil> Pupils { get; set; }
}

public class Pupil {
    public int ID { get; set; }
    public string PupilName { get; set; }
    public virtual ICollection<ClassRoom> ClassRooms { get; set; }
}

这是上下文的一部分

modelBuilder.Entity<Location>()
    .HasMany(l => l.ClassRooms)
    .WithMany(o => o.Pupils)
    .Map(m => m.MapLeftKey("PupilID")
        .MapRightKey("ClassRoomID")
        .ToTable("PupilClassRoomMM"));

因此，有一个名为“PupilClassRoomMM”的多对多表。

这一切都运行正常，但现在我想在PupilClassRoomMM表中添加一列。我试图制作这个模型，但Add-Migration没有得到它。

public class PupilClassRoomMM
{
    [Key, Column(Order = 0)]
    public int ClassRoomID { get; set; }
    [Key, Column(Order = 1)]
    public int PupilID { get; set; }
    public bool IsPrimary { get; set; }
}

错误是：

"PupilClassRoomMM: Name: The EntitySet 'PupilClassRoomMM' with schema 'dbo' and
table 'PupilClassRoomMM' was already defined.
Each EntitySet must refer to a unique schema and table."

如何将字段添加到已存在的多对多表中（我不想丢失其数据）。

多对多表作为具有额外列的模型

0 个答案: