The Persistence layer is covered early in this book for two reasons:
• Persistence, data storage, and Object/Relational (O/R) mapping components can provide a base for many applications. In a traditional bottom-up design, this area may be designed first within the architecture.
• Persistence is where many applications go wrong and where you might first look when they start to have trouble. That trouble could be performance, security, or functionality related. Data drives many applications, so you might focus on this particular aspect of the application.
I mentioned in earlier chapters that organizations expect the development team to be experts on new technology even as they continue to add new requirements ...