Magnus,
You can always provide the reasons/assumptions to justify your design decisions. But please make sure that you cross-check those with the given requirements so that there shouldn't be any contradictions.
My suggestion : Use Entity Beans than writing all JDBC code from scratch. For reading operations (if performance is a major concern), you can follow the Fast Lane Reader
pattern. For others, its better to use Entity Beans.
[ April 03, 2007: Message edited by: Joseph A Alexander ]