pimbrouwers / lunchpail

.NET Standard Unit of Work implementation for ADO.NET

LunchPail

LunchPail is a .NET Standard compliant Unit of Work implementation for ADO.NET. The UoW is the workhorse of the data context, so the project was dubbed "lunch pail" as a reference to blue collar athletes.

Getting Started

1. Register the context within your IoC container (.NET Core shown below using SQL Server):

//startup.cs
public void ConfigureServices(IServiceCollection services)
{
  //rest of code...

  //context
  services.AddTransient<IDbConnectionFactory>(options =>
  {
    var builder = new SqlConnectionStringBuilder(Configuration.GetConnectionString("DefaultConnection"));

    return new DbConnectionFactory(() =>
    {
      var conn = new SqlConnection(builder.ConnectionString);

      conn.Open();
      return conn;
    });
  });
  services.AddScoped<IDbContext, DbContext>();

  //repositories (we'll add this later)
}

2. Create a domain class to represents your database object.

public class Product
{
  public int Id { get; set; }
  public string Name { get; set; }
}

3. Create a repository with a dependency on IDbContext

public interface IProductRepository
{
  Task<Product> Read (int id);
}

public class ProductRepository : DbRepository
{
  public ProductRepository(IDbContext dbContext) : base(dbContext) { }

  public Product Read(int id)
  {
    return Connection.QuerySingleOrDefault<Product>("select * from dbo.Product where Id = @id", new { id }, transaction: Transaction);
  }
}

4. Register the repository with your IoC container (.NET Core shown below):

//startup.cs
public void ConfigureServices(IServiceCollection services)
{
  //repositories
  services.AddScoped<IProductRepository, ProductRepository>();
}

5. With the context and repository registered, you're free to inject this into your controller or service layer.

Note the invocation of dbContext.Commit() which must occur after every interaction is complete to ensure proper disposal of the connection. This is true whether the interaction is a read or write.

public class ProductService
{
  private readonly IDbContext dbContext;
  private readonly IProductRepository productRepository;

  public ProductService (
    IDbContext dbContext,
    IProductRepository productRepository)
  {
    this.dbContext = dbContext;
    this.productRepository = productRepository;
  }

  public Product Read(int id)
  {
    var product = productRepository.Read(id);
    dbContext.Commit(); // You MUST call commit after all interactions

    return product;
  }
}

Built with ♥ by Pim Brouwers in Toronto, ON.

lunchpail's Issues

Implementation question

@pimbrouwers Please help me on below points.

1. May i know why we have to commit (dbContext.Commit();) the transaction for SQL statements which only get the information from database (Like Read operation). Can we ignore Begin Transaction for operations like Read from SQL.

2. I am using Dapper as middle layer. I have registered the context exactly like how you provided the instructions in startup.cs file. The problem that i am seeing here is with in same controller method call if i am making two database calls (both are read), First call is working fine but the second one is throwing below exception as i believe context was already closed due to
   commit was called after completing the fist DB call. Please let me know if i am missing anything.

System.InvalidOperationException: The ConnectionString property has not been initialized.
at System.Data.SqlClient.SqlConnection.PermissionDemand()

3. Any async call being made with this code resulted in below exception. Please guide me how to invoke async calls.

   DB call: await Connection.QueryAsync(sQuery,transaction:Transaction);

System.InvalidOperationException: Invalid operation. The connection is closed.
at System.Data.SqlClient.SqlCommand.<>c.b__122_0(Task`1 result)

4. I am new to .net core world. As per below IOC registration, according to my understanding every time application gets a new request then connection will be opened. It is possible some requests don't need a database connection in that case application is opening a SQL connection but it will not be closed. Please let me know if my understanding is correct.

services.AddTransient(options =>
{
var builder = new SqlConnectionStringBuilder(Configuration.GetConnectionString("DefaultConnectionString"));

            return new DbConnFactory(() =>
            {
                var conn = new SqlConnection(builder.ConnectionString);

                conn.Open();
                return conn;
            });
        });

Please help.