A Word on ADO.NET

ADO.NET is part of Microsoft's new .NET architecture—the company's redesign of application development tools to better suit the needs of web development. ADO.NET is a significant evolution of ADO. It looks at the problems of web development and addresses shortcomings of ADO's solution. The problem with ADO's solution is that it is based on COM. For one- and two-tier applications, COM imposes few problems, but in the world of web development, it is unacceptable as a transport mechanism. COM suffers from three primary problems that limit its use in web development: It (mostly) runs only on Windows, the transmission of recordsets from one process requires COM marshalling, and COM calls cannot penetrate corporate firewalls. ADO.NET's solution to all these problems is to use XML.

Some other redesign issues focus on breaking the ADO recordset into separate classes. The resulting classes are adept at solving a single problem instead of multiple problems. For example, the ADO.NET class currently called DataSetReader is similar to a read-only, forward-only, server-side recordset and, as such, is best suited to reading a result set very quickly. A DataTable is most like a disconnected, client-side recordset. A DataRelation shares similarities with the MSDataShape OLE DB provider. You can see that your knowledge of how ADO works is of great benefit in understanding the basic principles of ADO.NET.