Difference between: Restful Webservices using Entity Class,Restful Webservices using Database, and Restful Webservices using Pattern

Question

While learning RESTful apis with java using netbeans, there are three types of web services.

1. Restful Webservices using Entity Class
2. Restful Webservices using Database
3. Restful Webservices using Pattern

I have designed the services using all the three methods, and also gone through the code snippets of all the services.

But i cant figure out the exact difference between these three types of web services.