Flowsy.Db.Sql 0.2.0

Flowsy Db Sql

This package includes implementations for interfaces defined in Flows.Db.Abstractions oriented to SQL databases.

Connection Factory

The class DbConnectionFactory implements the interface IDbConnectionFactory to create IDbConnection objects from a list of registered configurations identified by unique keys.

Unit Of Work

The class DbUnitOfWork implements the interface IUnitOfWork to create IDbTransaction objects from a given IDbConnection.

For example, to create an invoice, we may need to create two kinds of entities:

• Invoice
  • InvoiceId
  • CustomerId
  • CreateDate
  • Total
  • Taxes
  • GrandTotal
• InvoiceItem
  • InvoiceItemId
  • InvoiceId
  • ProductId
  • Quantity
  • Amount

A way of completing such operation from an application-level command handler could be:

public interface ISalesUnitOfWork : IUnitOfWork
{
    IInvoiceRepository InvoiceRepository { get; }
    IInvoiceItemRepository InvoiceItemRepository { get; }
}

public class SalesUnitOfWork : DbUnitOfWork, ISalesUnitOfWork
{
    private readonly IInvoiceRepository? _invoiceRepository;
    private readonly IInvoiceItemRepository? _invoiceItemRepository;
    
    public SalesUnitOfWork(IDbConnection connection) : base(connection)
    {
    }
    
    public IInvoiceRepository InvoiceRepository
        => _invoiceRepository ??= new InvoiceRepository(Transaction);
    
    public IInvoiceItemRepository InvoiceItemRepository
        => _invoiceItemRepository ??= new InvoiceItemRepository(Transaction);
}

public class CreateInvoiceCommandHandler
{
    private readonly IUnitOfWorkFactory _unitOfWorkFactory;
    
    public CreateInvoiceCommandHandler(IUnitOfWorkFactory unitOfWorkFactory)
    {
        _unitOfWorkFactory = unitOfWorkFactory;
    }
    
    public async Task<CreateInvoiceCommandResult> HandleAsync(CreateInvoiceCommand command, CancellationToken cancellationToken)
    {
        // Begin operation
        // IUnitOfWork inherits from IDisposable and IAsyncDisposable, if any exception is thrown, the current operation shall be rolled back
        await using var unitOfWork = _unitOfWorkFactory.Create<ISalesUnitOfWork>();

        var invoice = new Invoice();
        // Populate invoice object from properties of command object 
        
        // Create the Invoice entity
        var invoiceId = await unitOfWork.InvoiceRepository.CreateAsync(invoice, cancellationToken);
        
        // Create all the InvoiceItem entities
        foreach (var item in command.Items)
        {
            var invoiceItem = new InvoiceItem();
            // Populate invoiceItem object from properties of item object
            
            // Create each InvoiceItem entity
            await unitOfWork.InvoiceItemRepository.CreateAsync(invoiceItem, cancellationToken); 
        }

        // Commit the current operation        
        await unitOfWork.SaveAsync(cancellationToken);
        
        // Return the result of the operation
        return new CreateInvoiceCommandResult
        {
            InvoiceId = invoiceId
        };
    }
}