Web Services Architecture - Multiple services & multiple database connections?

Could someone please direct me to some good documentation or feedback here on what are best practices for implementing web services in an application that handles different concerns? For example, should I create different 开发者_StackOverflow中文版services, one that handles security, (AuthService), one that handles data-entry for customer service reps, (CRUDService), BillingService and so on or should I just encapsulate all these "services" into one, e.g. ApplicationService? Basically, I am asking if it is bad design to create multiple services (files) within one application. Can some of you note on your experiences or what you've experienced? Also, let's say three of the listed services from above connect to the same database, but are actually hitting totally different concerns, e.g. one is for all transactions like CRUD, and the other one is for purely reporting purposes. Should I create two services here, one CRUDService and the other for ReportingService? Is it bad to create two different database connections via these 2 services? Or how can I share the same database connection with different services?

I think there is a tendency among publicly available services to just dump everything into one service. Which, may not be a bad idea for a publicly available API. It just makes it easier for developers. However, for any project i work on, i try to break things down into logical groups. This way your client doesn't need to be inheriting functionality it may not need. Updating services would also be a slightly easier task because you're only affecting a certain subset of your web service framework and not everything. So if your service contract breaks and your clients no longer support it, they may still be able to use other parts of your system, but not that particular one. Where as if you break a contract on your aggregated service, everything fails. Finally, if you have to implement something like a fail-over support, you have more flexibility to choose which service requires more fail-over nodes, allowing you to better manage your resources allocation.

If you want best practices take a look to the SOA Design Pattern Catalog