EF Code First创建的外键超出预期

Question

I'm working on an application that should be able to switch between code first and database first, so I took the code generated by EF (from db first) and tried to create code first. In the end, the databases were the same, except this Activity table that besides TypeId and SubTypeId contains also Type_Id and Type_Id1 both nullable and I don't understand why.

public class Activity
{
    public int Id { get; set; }
    public int TypeId { get; set; }
    public int? SubTypeId { get; set; }

    [ForeignKey("TypeId")]
    public virtual Type Type { get; set; }
    [ForeignKey("SubTypeId")]
    public virtual Type Type1 { get; set; }
}

public class Type
{
    public int Id { get; set; }
    [StringLength(50)]
    [Required]
    public string Name { get; set; }

    public virtual ICollection<Activity> Activities { get; set; }
    public virtual ICollection<Activity> Activities1 { get; set; }
}

Answer 1

Hope below will work for you

  public class Activity
    {
        public int Id { get; set; }
        [ForeignKey("Type")]
        public int TypeId { get; set; }
        [ForeignKey("Type1")]
        public int? SubTypeId { get; set; }
        public virtual Type Type { get; set; }

        public virtual Type Type1 { get; set; }
    }