EF code first Reference key as primary key

Question

Landed up in a quite ridiculous situation here.

I'm coding in EF core, ASP.NET core, Visual Studio 2017 community.

I have a model which does not have a primary key like:

public class LoginRecord
{
    public User User { get; set; }

    public int UserId { get; set; }

    public DateTime LastLogin { get; set; }
    public int LoginCount { get; set; } 
}

where User is a table with all the fields like name, email etc.

When I do add-migration , an error pops up saying:

The entity type 'LoginRecord' requires a primary key to be defined.

Then I tried by adding the [Key] annotation to the UserId field like this:

public class LoginRecord
{
    public User User { get; set; }

    [Key]    
    public int UserId { get; set; }

    public DateTime LastLogin { get; set; }
    public int LoginCount { get; set; } 
}

but now, EF creates a new column called UserId1 which becomes the foreign key.

I need the UserId to be just a reference key and don't need a primary key for this table.

Is it possible? If yes please help!

Answer 1

You should add an primary key. I've learned that every table should get a field which is named like the table + id. You could also name it id if you like it more. :) So that every record gets unique.

So I would advice you to change your model to something like this:

public class LoginRecord
{
  [Key]
  public int LoginRecordID {get; set;}

  public User User { get; set; }

  public int UserId { get; set; }

  public DateTime LastLogin { get; set; }
  public int LoginCount { get; set; } 
}

Answer 2

Try:

[ForeignKey("UserId"), Column(Order = 0)]
public int UserId { get; set; }