ActiveX Data Objects (ADO).
ADO.NET provides consistent access to data sources such as SQL Server and XML, and to data sources exposed through OLE DB and ODBC.
ADO.NET provides the most direct method of data access within the .NET Framework. For a higher-level abstraction see the ADO.NET Entity Framework.
The ADO.NET classes are found in System.Data.dll, and are integrated with the XML classes found in System.Xml.dll.