No matter what programs you develop, there always exists a bottom line: you must know how to access and manipulate data. While data can be stored in many places, large quantities of frequently accessed data must be structured appropriately in relational databases like SQL Server. Meanwhile, data access in .NET is achieved through the ADO.NET classes--which essentially replace ActiveX Data Objects (ADO), combining ADO-style ease with the power of XML.
Scott Allen has a master's degree in computer science from Shippensburg University of Pennsylvania. He's a Microsoft Certified Solution Developer, and regularly serves as an adjunct faculty member at various colleges in Maryland and Pennsylvania.