The MDAC SDK contains several sample applications that demonstrate usage of ADO and RDS code. For more information about these samples, see ADO Sample Applications.
The ADO documentation also contains code examples in multiple languages, which are included as topics within this online help. For more information about these examples, see ADO Code Examples.
Many other sample code resources are available. Visual Studio documentation and the MSDN Library contain a variety of sample applications and documentation that can help you learn about ADO and RDS.
Visual Studio Samples
Visual Studio Documentation