[Zope] zope db question

Hi I am new phyton and zope programmer. I have to make a product for zope and i must use a list of groups with a lot of data. I´m wondering if i must to use a list of persistent objects or if it´s better use a database like gadfly with tables or another one. I´m a little confuse. I think that the two solutions are possible but i don´t know whitch is better. sorry for my bad english. thanks. jose from Spain, Europe.