Data base connection through EJB

Hi,

I would like to develop WD application that access to SQL DB

I thaught of doing it using EJB and using it as model in the WD appliation.

My questions are what type of EJB do I need to use, entity bean or session bean and what are the main difference between of them ?

I read in other threads that they recomend to make a web service out of the EJB, Is that correct ? The WD application should be able to use also EJB as model in addtion to web service (and RFC)

I would appriciate a refernce to a simple tutorial if there is one

Thanks

Ami