<?xml version="1.0" encoding="utf-8" ?>

<configuration>

  <connectionStrings>

    <add name="Northwind" providerName="System.Data.SqlClient"

      connectionString="Data Source=.;Initial Catalog=Northwind;

                       integrated security=SSPI" />

  </connectionStrings>

class Program

{

    static void Main(string[] args)

    {

        //from the System.Configuration assembly

        ConnectionStringSettings cnstrSettings = ConfigurationManager.ConnectionStrings["Northwind"];

        DbProviderFactory factory = DbProviderFactories.GetFactory(cnstrSettings.ProviderName);

        using(DbConnection connection = factory.CreateConnection())

        using(DbCommand command = factory.CreateCommand())

        {

            connection.ConnectionString = cnstrSettings.ConnectionString;

            connection.Open();

            command.Connection = connection;

            command.CommandText = "SELECT * FROM Customers";

            using (DbDataReader reader = command.ExecuteReader())

            {

                int customerIdOrdinal = reader.GetOrdinal("CustomerID");

                int companyNameOrdinal = reader.GetOrdinal("CompanyName");

                while (reader.Read())

                {

                    Console.WriteLine(String.Format("CustomerID = {0}, Company Name = {1}",

                        reader.GetString(customerIdOrdinal),

                        reader.GetString(companyNameOrdinal)));

                }

            }

        }

    }
}