C#•3mo ago

✅ EF multicolumn index by only having navigational property in the model

Hi, I am trying to create a multicolumn index and a foreign key would be part of it. With the help of the navigation property I am able to specify the foreign key, but I am unable to create the index. The syntax of the HasIndex is wrong, explicit string value cannot be used.

c#
public class Dog
{
    public Guid Id {get; set; }
    public string Alias {get; set; }

    public Owner Owner { get; set; } // navigation property
}

c#
public class Dog
{
    public Guid Id {get; set; }
    public string Alias {get; set; }

    public Owner Owner { get; set; } // navigation property
}

c#
  private static void Configure(EntityTypeBuilder<Dog> builder)
  {
      builder.HasOne(b => b.Owner)
          .WithMany()
          .HasForeignKey("OwnerId");
      
      builder.HasIndex(b => new { "OwnerId", b.Alias })   // Can't do this, but this is what I want to achieve
          .IsUnique();
  }

c#
  private static void Configure(EntityTypeBuilder<Dog> builder)
  {
      builder.HasOne(b => b.Owner)
          .WithMany()
          .HasForeignKey("OwnerId");
      
      builder.HasIndex(b => new { "OwnerId", b.Alias })   // Can't do this, but this is what I want to achieve
          .IsUnique();
  }

2 Replies

Keswiik•3mo ago

You can define an explicit OwnerId foreign key property and use that to build your index

Core•3mo ago

Thanks! That works

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✅ EF multicolumn index by only having navigational property in the model