Entity Framework Code First - Cannot insert duplicate key in object 'db'

Question

I\'m using the new EF code first to one project of mine, and i\'m getting a weird error, my mode is:

abstract class Member
{
   public virtual int MemberId;
  ..         


        

Answer 1

1. Is MemberId autoIncremented?
2. Have you checked the id of your created users (with console.Writeline for exemple)?

3. Does it work if you do the following:

   x = ctx.Users.Create();        
   x.Name = "SomeUser";        
   ctx.SaveChanges();        
   y = ctx.Users.Create();        
   y.Name = "SomeUser2";        
   ctx.SaveChanges();
   

You should try to attach your entity before you modify it.

Answer 2

• I also had an issue with duplicate keys. For me the reason was that I mistakenly used

  Id = new Guid()

instead of

Id = Guid.NewGuid()

in a factory method for initializing my database.

• This related stackoverflow question might also give some further hints: Cannot insert duplicate key in object 'dbo.User'.\r\nThe statement has been terminated

Answer 3

I just came across this. Like the marked answer states, TPC doesn't set the key to an identity. So you can use an annotation for it:

[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public int ID { get; set; }

Answer 4

I just tested it and tables of derived types in TPC (table per concrete type) inheritance don't have PK defined as identity in EF 4.1 RC.