Reporting Services provides access to SQL Server, Oracle, ODBC, and OLE DB data sources as part of its standard features. For many reporting scenarios, connecting to a database and running a query is all that is needed to get all the information you need to report upon. But what happens if you want to use a DataSet as your data source? For example, maybe you already have a middle tier that processes your data to conform to your business logic and produces a DataSet as a result. Or maybe you don't, but you nonetheless want to manipulate your raw data prior to reporting in ways that are a better fit for a Microsoft Visual Basic or C# implementation than a SQL implementation, and a DataSet would be the logical end result of such processing. Well, fortunately, it is possible to do this. It is even relatively easy, once you work out what parts of the data processing extension interfaces really have to be implemented to wrap up a DataSet in a way that Reporting Services can use.

In this article, we'll take a look at creating and deploying a simple data processing extension that can be used to provide DataSet data to a Reporting Services report.