Why should you care?

ShopNest stores bulky SEO metadata separately from Product core columns — one-to-one keeps hot catalog queries lean.

See it live — copy this example

Paste into a .NET project with EF Core packages, then run with LocalDB/SQL Server (dotnet ef / dotnet run).

public class ProductDetail
{
    public int ProductId { get; set; } // PK + FK
    public Product Product { get; set; } = null!;
    public string LongDescription { get; set; } = "";
    public string MetaKeywords { get; set; } = "";
}

modelBuilder.Entity<ProductDetail>()
    .HasOne(d => d.Product)
    .WithOne(p => p.Detail)
    .HasForeignKey<ProductDetail>(d => d.ProductId);

What happened?

• ProductId serves as both PK and FK to Product.
• WithOne/HasForeignKey configures shared-primary-key one-to-one — common for extension tables.

Practice next

1. Add ProductDetail with ProductId as PK/FK.
2. Configure WithOne in Fluent API and migrate.
3. Query with Include(p => p.Detail) only when detail page needed.
4. Make one-to-one optional — nullable ProductId vs required detail.
5. Query split: load Product first, Detail second with explicit load.

Remember

One-to-one uses unique FK or shared PK. Split heavy columns into extension entity. Load detail navigation only when needed.

ShopNest product detail tab

Listing API skips ProductDetail; detail page Include Detail for long description.

Outcome: Fast category scroll; rich SEO fields only on product page.