Introduction

This chapter brings you up to speed on the ADO.NET classesthe foundations and structures upon which all ADO.NET applications are built. In subsequent chapters, I'll apply these ADO.NET classes to a wide variety of tasks you'll use in your applications. I suggest touring the wide streets of the ADO.NET object model and exploring the darker streets and alleys of the underlying base classes from there. To this end, I discuss the ADO.NET namespace in several sections to help you better understand which parts of ADO.NET leverage the others. I'll also briefly examine the underlying Framework base classes. The classes you code against inherit from base classes, so it's interesting (but not critical) to know what functionality they implement. No, you don't really need to know that the SqlConnection class inherits from DbConnection class that inherits from IDbConnection, but for those of you that like to know how ADO.NET is implemented behind the scenes, I'll provide a pointer or two. Don't be put off by the number of examples in this chapterthis is where I roadmap later chapters to let you explore implementation details and examples later on.

Over the last eight years or so, I've written four books and countless articles on ADO.NET. I struggled with the question of cutting and pasting from those books into these pages, but I decided to simply update you on the most recent changes, highlight the Visual StudiotoADO.NET code generators, and point you toward my old books and several others whose authors I respect. Sure, I've added quite a bit of new content here and several new examples. Frankly, there are really too many books out there on ADO that say about the same thing. That's the publisher's fault. I'm not going to wade into that street fight swinging. Instead, I'll sit back, pick a couple of the winners, and send you to them. Yes, my ADO and ADO.NET Examples and Best Practices (Apress, 2002) is dated, but you'll be able to find it in used bookstores. Be sure to see my Suggested Reading List for more titles.

If you really want to know how ADO.NET does what it does behind the scenes, I suggest using one of the publicly available class browsers such as Lutz Roeder's Reflector^[1]. These tools reverse-engineer the source code that's used to implement Framework classes. I've made the developers at Microsoft a bit crazy by telling them how to fix bugsreferencing the source code in the framework when I do so.

^[1] See www.aisto.com/roeder/dotnet/