After writing DevelopMentor's Essential OLE DB class and teaching it to provider writers (and detail-oriented consumer writers) for a few years, I always thought that a good way to get myself acquainted with the new data model was to write a new database client provider/driver/etc whenever the model changed. I wrote a simple .NET data provider during .NET alpha 1 and published an article in MSDN magazine about it in Dec 2001. Well, the model changed again.

ADO.NET 2.0 enhanced the data provider model in some pretty revolutionary ways. It added something that was always needed, a factory for providers. This class (System.Data.Common.ProviderFactories) gets a list of providers or a provider-specific factory class (e.g. SqlClientFactory). The provider-specific factory can be used to get provider-specific Connection, Command, etc, instances. Providers that want to participate now have a special place in the config file. The 4 Microsoft providers are listed in machine.config.

In addition to this change, the new provider model is based on base classes rather than interfaces (although interfaces are still there for backward compatibility). Provider writers implement classes that derive from DbConnection, DbCommand, etc. This allows adding new functionality without breaking backward compatibility.

So I've updated the provider and posted the update on my website. The updated provider uses base classes and also has a Provider Factory class. There's also a sample program that uses it. I didn't put the provider in machine.config, but have an app.config that adds it.

An overview of the new model is provided in this MSDN online article, and two more are in the works. Look for them in MSDN online.

Enjoy.

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