Book Review: Programming Entity Framework - Code First

Title: Programming Entity Framework: Code First Author: Julia Lerman, Rowan Miller Level: Beginner to Intermediate Publisher: O'Reilly Media Pages: 176 Rating: 4 of 5

EF 4.0 provides two approaches for working with entities, viz. Database First and Model First. In the former case you design a database before starting your application development. Then you use Entity Data Model Designer of Visual Studio to design a data model visually by dragging and dropping tables from the database onto the designer. In the case of Model First development you use Entity Data Model Designer to design data model classes manually. You then specify the database connection to be used in the application. In any case you use Entity Data Model Designer to generate your data model classes. This approach though useful at many places has its own shortcoming. The "visual designer" based approach taken by Entity Framework doesn't take care of existing data access classes (POCO style). You either need to drop them altogether and re-create them using the designer or use EF only for new development. Luckily, Microsoft introduced Code First as a supplement to the existing EF infrastructure that can be of great use in such scenarios. As the name suggests Code First approach skips the "visual designer" altogether, rather you code your classes (or use existing ones as a base) and then make them EF aware by applying attributes and such stuff. If this sounds interesting to you then probably you should pick Programming Entity Framework: Code First by Julia Lerman and Rowan Miller.

The book provides a concise understanding of Code First in 176 pages, yet it's not a pocket reference kind of book. Diagrams, screen shots and code snippets are scattered throughout the book. The book consists of eight chapters.

The first two chapters provide an introduction to Code First. Firstly, they give you idea as to what you can do and what you can't with Code First. Secondly, you develop a complete example that illustrates many pieces of Code First such as data annotations and fluent API. 

Chapter 3 discusses in detail the conventions and configurations for property attributes. These are the attributes that you use to decorate class properties to mark them as primary key, length, nullability and so on. It also covers how data types such as time stamp and decimal can be represented and ends with information on representing complex types.

Chapter 4 talks about conventions and configurations for relationships. Topics covered include multiplicity, foreign keys and inverse navigation properties. Further, it shows how to deal with cascade deletes and how to work with Many-to-Many and One-to-One relationships.

Chapter 5 is devoted to conventions and configurations for database mappings and covers many aspects of how Code First deals with database and tables. After covering basics such as mapping class name with table and property names with columns it explains scenarios such as mapping multiple entities to one table, mapping one entity to multiple tables, preventing properties from getting included in the model and mapping inheritance chains. The chapter concludes with discussion of controlling the foreign keys.

Chapter 6 covers various aspects related to database in terms of its creation and location. It also discusses how to seed sample data during database initialization process.

Chapter 7 deals with advanced scenarios such as mapping to database objects that are not tables (Views and Stored Procedures). Further, it talks about overriding the default behavior of model caching and working with Entity Data Model Metadata table (EdmMetadata).

Chapter 8 concludes the book by pointing to the future of Code First and talks in brief about Code First Migrations and Entity Framework Power Tools.

To summarize, Programming Entity Framework: Code First is a neatly written and concise coverage of all the important aspects of Code First development. If you are a developer looking to develop data driven applications using Code First technology then this book will be a great choice. If you wish to master the overall EF concepts (not just Code First) I would also suggest you to read Programming Entity Framework also by Julia Lerman.