I normally utilize the “Web Service Software Factory” to structure and implement my services.  This package greatly decreases the time spent on the mundane tasks of exposing your business logic to the service layer. 

One could argue that exposing business logic is quite simple, add a WCF service to your project and write your business logic in the *.svc file.  However, we are here to write loosely coupled code.  To this end, one can use multiple dynamic link libraries (.dll) to organize one code.  Moreover, by judicially choosing where objects belong, one can apply the principles of separations of concerns.

The “hands on lab” for the web service factory is top notch.  The modeling edition allows one to use a graphical approach to define data and services contacts quickly and correctly.  Below are the data contract and the service contract files needed to expose a service with a DBinsor configuration file.  Furthermore, I have included the projects contained in the solution file.

Data Contract:

         Service Contract:

         Solution: