Extending Reporting Services - Professional SQL Server 2005 Reporting Services - page 541

' Don't change. Put cleanup code
'in Dispose(ByVal disposing As Boolean) above.
Dispose(True)
GC.SuppressFinalize(Me)
End Sub

'Don't change
Protected Overrides Sub Finalize()
Dispose(False)
MyBase.Finalize()
End Sub

End Class

You will be using this Interface AutoComplete feature for the remainder of this chapter. If you are using
Visual Studio 2003, you will have to create these methods manually, or download the source and revert
to the old “cut and paste.” The generated code for IDisposable is suitable for demonstration purposes,
so I won't repeat this code for each object but simply indicate that it is required.

Data Processing Extensions — a Detailed Look
Reporting Services allows you to access data from traditional data sources such as relational databases
using the existing .NET data providers. The following providers are supplied as part of the .NET
Framework supplied by Microsoft:

❑ ODBC

❑ OLE DB

❑ Oracle

❑ SQLClient

Data processing extensions are components that allow you to access data for use within Reporting
Services. If that implies a “.NET data provider” to you, then congratulations are in order. These two types
of data access objects are very similar and are based on a common set of interface definitions. If you have
already built a custom .NET data provider, you may use that provider with Reporting Services with no
modification. However, you also can extend your existing provider to provide additional functionality.

To begin, we need to discuss the similarities and differences between a standard .NET data provider and a
Reporting Services data processing extension. Let's start with some architectural information about data
providers in general, and then dive into the details of creating a custom data processing extension. The
.NET Framework has a data access object model that is very similar to that used in traditional COM-based
ADO. The ADO.NET object model is displayed below in Figure 13-2.

Prior to Service Pack 1 of SSRS on SQL2000, Reporting Service data providers were essentially the same
as the ADO data providers, except for the fact that Microsoft had implemented wrapper classes around
the .NET providers in order for them to meet the Reporting Service extension interface requirements.
The Reporting Services requirements were a subset of the data provider requirements. The program-
ming paradigm was the same as well.