ADO.NET vs. Classic ADO

1. Architecture

Classic ADO: Classic ADO is a COM-based technology used in languages like VB6 and ASP classic. It uses disconnected recordsets.

ADO.NET: ADO.NET is part of the .NET framework and is designed for .NET languages like C# and VB.NET. It uses connected data providers.

2. Language Support

Classic ADO: Used with languages supporting COM and ActiveX, like VB6 and ASP classic.

ADO.NET: Integrated with the .NET framework, used with .NET languages like C# and VB.NET.

3. Data Provider Model

Classic ADO: Uses a single Connection-Command-Recordset model.

ADO.NET: Offers a modular model with separate classes for connections, commands, data readers, and data adapters.

4. Data Access Model

Classic ADO: Primarily uses a disconnected recordset model.

ADO.NET: Provides both connected and disconnected data access models with datasets and data readers.

5. Performance and Scalability

Classic ADO: May be less efficient for large-scale applications.

ADO.NET: Designed for scalability and performance in modern, high-traffic applications.

6. .NET Framework Integration

Classic ADO: Not tightly integrated with the .NET framework.

ADO.NET: Built into the .NET framework, offering managed code advantages.

7. Asynchronous Operations

Classic ADO: Lacks built-in support for asynchronous operations.

ADO.NET: Provides support for asynchronous operations.

8. Source Code Example (ADO.NET)

Here's a simple C# example using ADO.NET to connect to a SQL Server database and retrieve data:

using System;
using System.Data;
using System.Data.SqlClient;

class Program
{
    static void Main()
    {
        string connectionString = "Data Source=YourServer;Initial Catalog=YourDatabase;Integrated Security=True";
        
        using (SqlConnection connection = new SqlConnection(connectionString))
        {
            connection.Open();
            
            string query = "SELECT FirstName, LastName FROM Customers";
            
            using (SqlCommand command = new SqlCommand(query, connection))
            {
                SqlDataReader reader = command.ExecuteReader();
                
                while (reader.Read())
                {
                    Console.WriteLine($"Name: {reader["FirstName"]} {reader["LastName"]}");
                }
                
                reader.Close();
            }
        }
    }
}

Expected Output (ADO.NET):

Name: John Smith
Name: Jane Doe
...

Source Code Example (Classic ADO)

Here's a simple VB6 example using Classic ADO to achieve the same task:

Dim conn As New ADODB.Connection
Dim rs As New ADODB.Recordset

conn.Open "Provider=SQLOLEDB;Data Source=YourServer;Initial Catalog=YourDatabase;Integrated Security=SSPI"

rs.Open "SELECT FirstName, LastName FROM Customers", conn

Do Until rs.EOF
    MsgBox "Name: " & rs("FirstName").Value & " " & rs("LastName").Value
    rs.MoveNext
Loop

rs.Close
conn.Close

Expected Output (Classic ADO):

A message box will pop up with the names retrieved from the database.

In summary, ADO.NET is the preferred choice for modern .NET applications, offering better performance, flexibility, and integration with the .NET framework compared to Classic ADO.