Question

I have two classes:

public class MultilingualString
{
  public int Id { get; set; }

  public string DefaultText { get; set; }

  public IList<Translation> Translations { get; set; }
}

and

public class Translation
{
    public string Language { get; set; }

    public string Text { get; set; }

    public MultilingualString Owner { get; set; }
}

Now, I’d like to have tables MultilingualStrings and Translations with the following schema:

MultilingualString
  ID INT PK
  DefaultText NVARCHAR

and

Translations
  StringID PK, FK
  Language NCHAR(5) PK
  Text NVARCHAR

But don’t know how to create my code first model mapping with EF4/EF5. Is this scenario possible with EF?

Answer 1

It’s not possible to create a mapping between your tables and your entities because you must expose the full primary key as property/properties in your entity classes. Your table Translations has a composite primary key (StringID+Language) but your entity Translation only has a part of this key (Language) as a property.

However, if you introduce the StringID as property in Translation the mapping should be possible:

public class Translation
{
    public int StringId { get; set; }
    public string Language { get; set; }

    public string Text { get; set; }

    public MultilingualString Owner { get; set; }
}

Mapping with Fluent API:

modelBuilder.Entity<Translation>()
    .HasKey(t => new { t.StringId, t.Language });

modelBuilder.Entity<Translation>()
    .Property(t => t.Language)
    .HasMaxLength(5)
    .IsFixedLength();

modelBuilder.Entity<Translation>()
    .HasRequired(t => t.Owner)
    .WithMany(m => m.Translations)
    .HasForeignKey(t => t.StringId);