When a datatable has multiple keys, the entity framework by default gets confused for mapping the primary keys. By assigning an Order value to the Column attribute when mapping the primary keys solves this problem. This Order value should be in the same order as these columns appear in the datatable.
using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;
namespace LeafyJava.Models
{
[Table("leafyjava.event")]
public class Event
{
[Key]
[Column("pub_id", Order = 0)]
public string PubId { get; set; }
[Key]
[Column("auth_id", Order = 1)]
public string AuthId { get; set; }
[Column("description")]
public string Description { get; set; }
}
}