Problem with the following error in EF Cannot insert the value NULL into column 'Discriminator

See more:

C#

C#4.0

entity-framework

Hi Everyone,

I have the following poco class in library.

public class Product
   {
       [Key]
       public long ID { get; set; }
       public string Name { get; set; }
       public int? StockQuantity { get; set; }
       [Column(TypeName="nvarchar")]
       [MaxLength(50)]
       public string Identifier { get; set; }
       public DateTime? ReleaseDate { get; set; }
       public decimal? DefaultPrice { get; set; }
       public virtual ICollection<Language> ProductLanguages { get; set; }
       public virtual ICollection<Region> ProductRegions { get; set; }
       public virtual ICollection<Price> ProductPrices { get; set; }
       public virtual ICollection<Link> ProductLinks { get; set; }
       public virtual ICollection<Order> Orders { get; set; }
   }

and I have serveral other poco classes referencing this class like the below

public class Link
    {
        [Key]
        public Int32 ID { get; set; }
        public string Rel { get; set; }
        public string Href { get; set; }

        public virtual ICollection<Product> LinkProducts { get; set; }
    }

I am also using database migrations with the -EnableAutomaticMigrations flag.

My problem is when I call the method SaveChanges() in my DataContext I get the following error message.

"Cannot insert the value NULL into column 'Discriminator'

I know that this means that EF thinks that there is some class that is derives from product but this isn't true.

Can you please help with this problem?

Thank you,