Best practices: ext. database access

I've been tasked with using WebDynpro to create a sample report that extracts data from an external database (Oracle). Note that this external data source has absolutely nothing to do with SAP.

I currently have no idea how large the dataset it, but I'm curious how best to develop this with WebDynpro and the table view. I therefore have some (probably pretty basic) questions:

I suspect that I should use entity beans to implement the data layer - is this correct, or is there another way? note that I'm thinking long term, so I'm not looking for a quick-win (JDBC code embedded in the Dynpro component). For the reporting piece, access would obviously be read-only.

How do you handle large data sets? Say I have a table of a million rows - is there a 'built-in' way of scrolling over this dataset with a window of say 50 records? I could pre-load the context with all the data, but for large data sets this would not be possible.

Instead of using an EJB as the direct data-layer interface, how about exposing the EJB via a web service. Then I could query the web service, and restrict the number of rows fetched that way.

Any suggestions folks have would be most welcome. I'm a newbie to WebDynpro and J2EE development, and as such I'm kind of floundering in the large pool of documentation. Any sort of direction would certainly be helpful.

Thanks!