Could any body clarify these two expression for me ?
What are cons and pros of each one ?
I've just worked and familiar with CodeSmith and Linq to sql among all ORM Tools
It refers to whether you can disconnect the database session and still expect the entities to be "alive". In disconnected ORMs you can disconnect and reconnect a database session (e.g. between web page requests) while retaining entity objects (e.g. in a web session state).
Personally I prefer not to work in disconnected mode (I'm mostly using NHibernate), because although it seems to simply things there will sometimes be side effects that are tricky to debug.