Keyless Entity Types in EF Core: Query Data Without Primary Keys

Not everything in your database needs a primary key. Sometimes, you just want to query views, stored procedures, or raw SQL results without forcing a unique identifier on them. That’s where Keyless Entity Types in Entity Framework Core come in!

If you’ve ever struggled with querying database views, reports, or read-only datasets, this feature is exactly what you need. Let’s dive into what Keyless Entity Types are, when to use them, and how to make them work in EF Core.

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What Are Keyless Entity Types?

In EF Core, a Keyless Entity Type is an entity that does not require a primary key. Unlike standard EF Core entities that map to tables with primary keys, keyless entities are ideal for queries that don’t need identity tracking—such as reports, read-only views, or raw SQL queries.

Key Features of Keyless Entity Types:

No primary key required – Useful for queries that don’t need a unique identifier.
Maps to database views, stored procedures, or raw SQL – Ideal for reporting and read-only datasets.
Cannot be updated – These entities are read-only in EF Core, preventing accidental modifications.

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When Should You Use Keyless Entity Types?

Database Views – If you have a SQL view that aggregates data across multiple tables, EF Core can query it without requiring a primary key.

Stored Procedure Results – If your app executes a stored procedure and expects complex results, Keyless Entity Types help map the output.

Raw SQL Queries – When you need custom SQL results that don’t neatly fit into a single table structure.

Read-Only Reports – If you’re generating reports that don’t modify data, Keyless Entity Types are perfect for performance-friendly queries.

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How to Define a Keyless Entity Type in EF Core

Let’s say you have a database view that provides a summary of order details, but it doesn’t have a primary key. Here’s how you’d map it in EF Core.

1. Define the Keyless Entity

public class OrderSummary
{
    public int OrderId { get; set; }
    public string CustomerName { get; set; }
    public DateTime OrderDate { get; set; }
    public decimal TotalAmount { get; set; }
}

2. Configure it in DbContext

public class AppDbContext : DbContext
{
    public DbSet<OrderSummary> OrderSummaries { get; set; }

    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        modelBuilder.Entity<OrderSummary>()
            .HasNoKey() // This makes it a Keyless Entity Type
            .ToView("View_OrderSummary"); // Maps it to the SQL view
    }
}

3. Querying the Keyless Entity

Since Keyless Entity Types are read-only, you can only query them, not insert, update, or delete.

var summaries = await context.OrderSummaries.ToListAsync();

foreach (var summary in summaries)
{
    Console.WriteLine($"Order {summary.OrderId} - {summary.CustomerName} - ${summary.TotalAmount}");
}

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Using Keyless Entities with Raw SQL Queries

Sometimes, you might need custom SQL queries instead of mapping to a database view. EF Core allows keyless entities to work with raw SQL queries using FromSqlRaw().

1. Define the Keyless Entity

public class ProductSales
{
    public string ProductName { get; set; }
    public int UnitsSold { get; set; }
}

2. Configure It in DbContext

public class AppDbContext : DbContext
{
    public DbSet<ProductSales> ProductSalesReports { get; set; }

    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        modelBuilder.Entity<ProductSales>().HasNoKey();
    }
}

3. Execute a Raw SQL Query

var salesReport = await context.ProductSalesReports
    .FromSqlRaw("SELECT ProductName, SUM(Quantity) AS UnitsSold FROM Sales GROUP BY ProductName")
    .ToListAsync();

foreach (var sales in salesReport)
{
    Console.WriteLine($"{sales.ProductName}: {sales.UnitsSold} units sold");
}

This lets you run custom SQL queries directly in EF Core while maintaining type safety!

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Things to Keep in Mind

Keyless Entity Types are Read-Only – You cannot use them with Add(), Update(), or Remove().

No Change Tracking – EF Core doesn’t track keyless entities, so you can’t modify them in-memory and expect EF Core to persist changes.

Must Be Configured in OnModelCreating() – Unlike regular entities, keyless types must be explicitly mapped in OnModelCreating().

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Wrap-Up: When You Need Data Without the Keys

Keyless Entity Types are a powerful feature in EF Core that lets you query data from views, stored procedures, and raw SQL queries without worrying about primary keys. They’re perfect for reporting, analytics, and read-only scenarios where identity tracking isn’t needed.

So, next time you need to query data that doesn’t fit neatly into an EF Core entity, remember: You don’t always need a key!

Are you using Keyless Entity Types in your EF Core projects? Let’s discuss in the comments!