ADO.NET

ADO.NET

In the past, Microsoft introduced its “universal” data access engine, ActiveX Data Objects (ADO), which was based primarily on four objects: the Connection, the RecordSet, the Command, and the Parameter objects. Although this system provided a common method for data access using OLE DB data providers, it maintained a connection to the data store. In distributed applications, this became more and more of a limita-tion. As a result, Microsoft created ADO.NET.

ADO.NET utilizes XML as a data-interchange mechanism between the data store and the application. By taking advantage of XML for use as a data-transport mechanism, ADO.NET is able to function under a disconnected environment, thus making distributed applications easier to write. The core elements of the ADO.NET architecture are the data set and the data provider. This architecture has been designed to separate data access from data manipulation. How can it accomplish this? The answer is really quite ingenious: The primary component for data manipulation is the data set. However, the data set does not maintain a connection to the data store. As a result, the data set can be processed without the need for a connection to the data store; the connection is main-tained by the data provider components.

An entire book could be devoted to the intricacies and nuances for the entire data-access strategy in Visual Studio .NET, but because this book is geared toward XML, this section will introduce the basic concepts necessary to understand how XML fits into ADO.NET. As a result, this section will not cover ADO.NET in its entirety. For more information, visit http://msdn.microsoft.com/vstudio/nextgen/technology/adoplus.asp.