[Zope] ZODB: When to use IDs when references?

[Thomas Guettler]

Up to now I used relational databases. Now I don't know when it is
better to use IDs and when to use references.

Background: I write a Multiple Choice Python Product. There is a list
of questions and a list of users. Both get combined in the "result"
class. Should the class "result" have references to the questions or
store the question-IDs?

Any ideas welcome!

-- 
Open Source Software Solutions 
Thomas Guettler <thomas@thomas-guettler.de>
http://www.thomas-guettler.de