Why should you care?

ShopNest must decrement correct warehouse bin during ship-from-store — inventory schema prevents selling air.

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 StockItem { public int ProductId { get; set; } public int WarehouseId { get; set; } public int Quantity { get; set; } public byte[] RowVersion { get; set; } = null!; }
public class StockMovement { public int Id { get; set; } public int ProductId { get; set; } public int Delta { get; set; } public string Reason { get; set; } = ""; }

var stock = await db.StockItems.FindAsync(productId, warehouseId);
if (stock!.Quantity < qty) throw new InvalidOperationException("No stock");
stock.Quantity -= qty;
db.StockMovements.Add(new StockMovement { ProductId = productId, Delta = -qty, Reason = "Ship" });
await db.SaveChangesAsync();

What happened?

• Composite key StockItem per product per warehouse.
• Decrement Quantity with movement audit row.
• RowVersion detects concurrent pickers updating same bin.

Practice next

1. Model Warehouse and StockItem with composite key.
2. Log every quantity change in StockMovement.
3. Use transaction for reserve + movement insert.
4. ExecuteUpdateAsync to bulk zero clearance warehouse stock.
5. Query low stock: Where(s => s.Quantity < reorderPoint).

Remember

StockItem tracks qty per warehouse. Movements audit every delta. Concurrency token on hot stock rows.

ShopNest ship-from-store

Order routing picks nearest warehouse StockItem and decrements with movement Reason Ship.

Outcome: Ops dashboard reconciles movements against carrier manifests.