EF 5代码优先播种自引用表

Question

Here's my code:

base class:

public class BaseEnt
{
    [Key]
    public int ID { get;set; }
    public DateTime InsertDate { get; set; }

    public int InsertUserID { get; set; }
    public DateTime UpdateDate { get; set; }
    public int UpdateUserID { get; set; }
    [Timestamp]
    public byte[] Timestamp { get; set; }

    public virtual User InsertUser { get; set; }
    public virtual User UpdateUser { get; set; }
}

user entity:

public class User:BaseEnt
{
    public string Username { get; set; }
    public string Fullname { get; set; }

    public virtual ICollection<User> InsertedUsers { get; set; }
    public virtual ICollection<User> UpdatedUsers { get; set; }

}

model creating:

    protected override void OnModelCreating(DbModelBuilder modelBuilder)
    {
        modelBuilder.Entity<User>()
                     .HasRequired(t => t.InsertUser)
                     .WithMany(t=>t.InsertedUsers)
                     .HasForeignKey(t => t.InsertUserID).WillCascadeOnDelete(false);
        modelBuilder.Entity<User>()
                     .HasRequired(t => t.UpdateUser)
                     .WithMany(t=>t.UpdatedUsers)
                     .HasForeignKey(t => t.UpdateUserID).WillCascadeOnDelete(false);

    }

Seed:

    protected override void Seed(MCFDataContext context)
    {
        context.Users.Add(new Entities.User {ID=1,Fullname="Rusty Boi ",Username="jhaskdhaksdhk",InsertUserID=1,UpdateUserID=1,UpdateDate=DateTime.Now,InsertDate=DateTime.Now });

    }

and here's the error i encountered in the seed part:

{"Unable to determine a valid ordering for dependent operations. Dependencies may exist due to foreign key constraints, model requirements, or store-generated values."}

Answer 1

what you have here is some sort of "chicken and egg" problem. Possible solutions:

• Make the foreign keys InsertUserID and UpdateUserID nullable
• Do a design change: Maybe the user table shouldn't have InsertUserID, UpdateUserID. this could be solved by introducing another base class which doesn't have the InsertUserID and UpdateUserID properties or something similar