Why should you care?

ShopNest checkout updates inventory and creates order through two repositories but commits once via IUnitOfWork.

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 interface IUnitOfWork
{
    IProductRepository Products { get; }
    IOrderRepository Orders { get; }
    Task<int> SaveChangesAsync(CancellationToken ct);
}

public class UnitOfWork(ShopNestDbContext db) : IUnitOfWork
{
    public IProductRepository Products { get; } = new ProductRepository(db);
    public IOrderRepository Orders { get; } = new OrderRepository(db);
    public Task<int> SaveChangesAsync(CancellationToken ct) => db.SaveChangesAsync(ct);
}

What happened?

• Single DbContext instance backs both repositories.
• SaveChangesAsync once persists all staged changes atomically.

Practice next

1. Inject IUnitOfWork Scoped per request alongside DbContext.
2. Call repositories then single SaveChangesAsync at end of use case.
3. Combine with explicit transaction for cross-context needs.
4. Add BeginTransactionAsync wrapper on UnitOfWork.
5. Register repositories lazy vs eager — measure DI complexity.

Remember

Unit of Work shares one DbContext session. One SaveChanges per business operation. Pairs naturally with repository interfaces.

ShopNest checkout unit

CheckoutHandler uses IUnitOfWork to add Order and decrement stock before single SaveChangesAsync.

Outcome: Partial updates impossible — both succeed or neither.