Great book for anyone thinking about using an object database. Db4o is an awesome database to use for your projects. This books is a great way to get yourself in the game. The only thing is that the book is written for version 5.2 and 5.7 is already available for download and the new stuff in 5.7 isn't in the book.

I used db4o during the last six months. I awaited this book for a long time. It provides much useful information about building applications using the db4o. Instead of the level of technical detail, the book is easy to read.

In the very interesting Part I, the concept of open source native object database is introduced along with little history where object database came from. It also provide some useful background with regard to why the relational data model is not an ideal fit for objects.

Part II step the reader through the processus of building a first db4o application and gives details for the inner working of db4o. The exemples are incrementally skilled with each step in the evolution of an application. It provide a lot detail on the topics covered in the earlier chapters. The chapters 7 through 9 are concerned with making the reader understand what each of the db4o parts actually does and how you can use the various functions to tune the behavior of the peristent part of your object application.

The chapters of the Part III are great reference materials and introduces the readers to the rules you need to keep in mind while you came from RDBMS. It compare db4o features compare to the traditional SQL query-driven application. Comparison between RDBMS and OODBMS is a common theme in each chapter of this book. This Part gives you a new and open mind about persistent data in object application. I am happy that it gives you when RDBMS is good and when OODBMS is better instead of seeking to make me believe that OODBMS is the universal solution (but from my own experience, when objects are complex, it is the only solution). You will understand how db4o features compare to the SQL query-driven approach, how db4o query performes and when it is suitable for your application.

I am happy by this book for two reasons. Firts, it provides much needed high-quality documentation for building fully object oriented applications. I mean object data model with object database. Second, it provides the information in an almost easy-to-understand progressive manner. I learned a lot more about db4o by reading this book, and I also learned a lot about object database in a more general sense. I recommend this book to anybody building an object application and don't want to tediously map objects to database table and depend on a string-based query language to manage and retreive the data.