c# - Mapping composite keys using EF code first

Question

Sql server table:

SomeId PK varchar(50) not null 
OtherId PK int not null

How should I map this in EF 6 code first?

public class MyTable
{
    [Key]
    public string SomeId { get; set; }

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

I've seen some examples where you have to set the order for each column, is that required?

Is there official documentation on this somewhere?

Answer 1

You definitely need to put in the column order, otherwise how is SQL Server supposed to know which one goes first? Here's what you would need to do in your code:

public class MyTable
{
  [Key, Column(Order = 0)]
  public string SomeId { get; set; }

  [Key, Column(Order = 1)]
  public int OtherId { get; set; }
}

You can also look at this SO question. If you want official documentation, I would recommend looking at the official EF website. Hope this helps.

EDIT: I just found a blog post from Julie Lerman with links to all kinds of EF 6 goodness. You can find whatever you need here.