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Cure Data Type 'Impedance Mismatch' With LINQ
Roger Jennings takes the LINQ technical preview bits for a test drive.
by Roger Jennings

Microsoft Professional Developers Conference, September 2005

General-purpose programming languages (GPPLs), such as VB, C#, and Java, suffer from a type-system disconnect with database programming languages (DBPLs), such as ANSI SQL, T-SQL and PL/SQL, and XML programming languages (XMLPLs) based on the XML Document Object Mode (XML DOM), such as XPath, XSLT, and XQuery. "Impedance mismatch" is an engineering term that's commonly applied to the incompatibility between type systems. As an example, audio engineers use transformers to convert the balanced outputs of studio-quality 600-ohm microphones to the high-impedance, unbalanced mic inputs of consumer-grade audio gear. Thus, you might equate Microsoft's new Language Integrated Query (LINQ) Project combined with VS 2005's new generic types as a "transformer" for .NET query languages.

A previous PDC2005 blog item and article by Peter Varhol provide links to downloadable C# and VB LINQ technical preview add-ins to VS 2005 (including the Express editions) and describe some of the basic objectives of the "LINQ Project." In this article, I'll describe my initial experiences with the technical preview bits that you can download here for C# and here for VB. Both previews require a recent VS 2005 Beta 2 version and, according to the Project LINQ Readme, won't run "on builds later than this Tech Preview," which include the recently-released RC0 drop. However, today's C# and Visual Basic LINQ Tech Preview links on The LINQ Project page state that the hands-on labs and compilers support the "release candidate versions of Visual Studio 2005" and its Express editions.