说明：  Working as an architect and consultant, I have noticed a severe dearth in the .NET community when it comes to the finer points of using design patterns to build data access layers. The Java camp has followed the patterns = reuse mantra for a long time, but the .NET side of the house is just starting to move in that direction. After scouring the Internet and bookstores, I have been shocked at how few books address using object-relational mapping patterns with .NET. The idea for this book has been in the back of my mind for a while, but I was always hesitant because of the deficiency in the native Microsoft tools. Now, with the Language-Integrated Query (LINQ) suite and the ADO.NET Entity Framework (EF), the object-relational mapping pattern can finally be realized in the .NET space. Although there are numerous books about LINQ, this book goes further and ties together the use of ORM design patterns with LINQ and Visual Studio. include source code.