Why should you care?

ShopNest checkout writes want normalized integrity; order history reads want denormalized speed.

See it live — copy this example

Paste into a C# console or class library project and run dotnet run.

public sealed record PlaceOrderCommand(string Sku, int Qty);
public sealed class PlaceOrderHandler
{
    public Task Handle(PlaceOrderCommand cmd)
    {
        Console.WriteLine($"WRITE order {cmd.Sku} x{cmd.Qty}");
        return Task.CompletedTask;
    }
}
public sealed class OrderHistoryReadModel
{
    public string GetHistory(string userId) => $"orders for {userId}"; // denormalized store
}

await new PlaceOrderHandler().Handle(new PlaceOrderCommand("HD-100", 1));
Console.WriteLine(new OrderHistoryReadModel().GetHistory("u1"));

Run Example »

Edit the code below and click Run to see the result in Toolliyo’s live editor.

What happened?

• Commands mutate write models; queries hit read models.
• They can share one DB with different tables or diverge fully.
• Accept short read lag when projected asynchronously.

Practice next

1. Run place + history sample.
2. Split write/read interfaces in your app.
3. Document lag for UI after write.
4. Return order id from handler.
5. Add GetById read model method.

Remember

Separate write/read paths. Optimize each side. Use when shapes diverge.

ShopNest orders CQRS

PlaceOrder writes; history reads a projection.

Outcome: Checkout stays simple; history stays fast.