c# - Entity Framework 6.1.3 Mapping Foreign key to non primary key

Question

The goal is to have an API with all the fields from the GravityZone with the name of the zone coming from the Zone table. I've tried several permutations of the following code without success. It's currently coming up with null for the Zone which I'm hoping to get either the name as a string or part of the object. I'm working with existing tables that I'm not able to modify.

Models:

public partial class Zone
{
    [Key]
    [Column("ZONE_ID")]
    public decimal ZoneId { get; set; }

    [Column("ZONE_CODE")]
    public decimal ZoneCode { get; set; }

    [Column("ZONE_NAME")]
    public string ZoneName { get; set; }

    public virtual ICollection<GravityZone> GravityZones { get; set; }
}

public partial class GravityZone
{
    [Key]
    [Column("GRAVITY_ID")]
    public decimal GravityZoneId { get; set; }

    [Column("ZONE_CODE")]
    public decimal ZoneCode { get; set; }

    [Column("ELEVATION")]
    public decimal Elevation { get; set; }

    [Column("REMARK")]
    [StringLength(2000)]
    public string Remark { get; set; }

    public virtual Zone Zone { get; set; }
}

Context (only the relational portion)

modelBuilder.Entity<Zone>()
    .HasKey(e => e.ZoneCode);

modelBuilder.Entity<GravityZone>()
    .HasRequired(e => e.Zones);

Everything else comes back great except for this part:

"Zones":null,

Answer 1

This is now possible in Entity Framework 7 (that is, EF Core 1.0).

From .Net Entity Framework User Voice Unique Constraint (i.e. Candidate Key) Support:

Support for this feature was added in EF Core 1.0 and we don’t have plans to add it in the EF6 codebase.