Author: Vijay P. Mehta
Published: JUL 2008
Pages: 408
ISBN10: 1-59059-965-9
ISBN13: 978-1-59059-965-5
URL: http://www.apress.co...w/9781590599655

[img]http://andreacol.net/files/media/image/BookCover_ProLINQOrmMapping.JPG[/img]

VOTE: 3/5

This book is organized in five parts: the first part explores the basics of Object-Relational Mapping with a brief on all existing patterns and tools. The second part examines LINQ to SQL from a practical standpoint, introducing the DataContext class and its behavior, the basics of DBML mapping options, how to construct relationships, joins and projections. Part three is the most interesting one, It introduces the Entity Framework with a fast-paced guide to mapping xml-based infrastructure known as Conceptual-Mapping-Storage models, which syntax and properties are explained quite well and formerly created ground-up, the latter wizard-like example is more suited for beginners who are new in ORMs. Chapter 6 introduces the ObjectContext class and how to deal with querying data with method-based and expressions approaches, inserting, updating and deleting the graph with Object Services. In chapter 7, the book explain how to manage and map class inheritance, it also introduces the Entity Client Provider API and how to query against Entity Data Model and Conceptual Model. Part four, illustrates with a use case approach, how to apply the topics of the preceding chapters in a practical example in which a domain model is mapped in a top-down manner. Chapter 10 and 11 concentrates concepts like top-down mapping approach, Persistence Ignorance (which is not supported by EF yet), Object Context and DTOs. The last chapter compares LINQ to SQL, Entity Framework and all other non MS options on the market, explaining their differences and why each of them fits better in different scenarios, the author put all these ORMs on the same scale, evaluating their features against a set of criteria used to score a good ORM tool.

Conclusions
I found this book interesting because It was the first one about ADO.Net EF, but if you are new to LINQ and want to learn all about the language enhancements shipped with .net framework 3.5 (on top of which LINQ is based) and the other flavors available (LINQ to XXX) I suggest to look for another one. This book in my opinion is best suited for people who are experienced enough with Domain Driven Design and ORMs and faced with the difficulties to accommodate the Object and the Relational "worlds". It explain how to use LINQ to SQL and Entity Framework to map in bottom-up and top-down approaches, the book is provided with good code samples and the solution used in the use case is available for download.