How to set the one-to-one relationship with fluent

Question

I have this two entities:

    public partial class Ficheros
        {
            public Guid Idfichero { get; set; }
            public long Iddocumento { get; set; }
            public byte[] Fichero { get; set; }

            public virtual Documentos IddocumentoNavigation { get; set; }
        }

public partial class Documentos
    {
        public Documentos()
        {
            ElementosDocumentos = new HashSet<ElementosDocumentos>();
        }

        public long Iddocumento { get; set; }
        public string Nombre { get; set; }
        public long? IdtipoDocumento { get; set; }
        public string Codigo { get; set; }
        public decimal? Espacio { get; set; }
        public string Unidades { get; set; }
        public long? Bytes { get; set; }

        public virtual ICollection<ElementosDocumentos> ElementosDocumentos { get; set; }
        public virtual Ficheros Ficheros { get; set; }
        public virtual DocumentosTipos IdtipoDocumentoNavigation { get; set; }
    }

In the database, IDFichero is an uniqueidentifier and in Documentos the IDDocumento is a big int autoincrement. The main table is Documentos, that has one and only one fichero, and it is requiered.

The examples that I have seen, it would make me that IDFichero was IDDocumento, but to store a file in the database I need that the ID is a uniqueidentifier.

Thanks.

Answer 1

The relationship you are describing in EF terms is one-to-one FK association with both ends required, Documentos being the principal and Ficheros the dependent.

EF does not support explicit FK for this type of association, so start by removing the Ficheros.Iddocumento property:

public partial class Ficheros
{
    public Guid Idfichero { get; set; }
    public byte[] Fichero { get; set; }

    public virtual Documentos IddocumentoNavigation { get; set; }
}

then use the following fluent configuration:

modelBuilder.Entity<Documentos>()
    .HasRequired(e => e.Ficheros)
    .WithRequiredPrincipal(e => e.IddocumentoNavigation)
    .Map(m => m.MapKey("Iddocumento"));