[Zope] Need Zen advice, how to organize invoice items which I'm considering making folderish

[Milos Prudek]

> queries? Sometimes you're thinking of the invoices as grouped by dates,
> other times you're looking for the aggregate of other properties, such
> as CustomerID. I need to be able to create things like "show all year
> 2001 invoices for customers in the 90210 zip code" as well as, "Show the
> average invoice amount for the the top 10 customers."


This paragraph of yours describes classic SQL situation. Don't try it 
with ZODB.

I make decisions about whether to use ZODB or SQL like this:

STEP 1: Would the task benefit from ZODB: if no, use SQL. if yes, go to 
step 2

STEP 2: Would ANY of ZODB shortcommings affect adversely the task? if 
yes, use SQL. If no, use ZODB.

ZODB is generally fine but you should take some of information provided 
by zope.com with a pinch of salt.
ZODB is simply not as mature as most SQL solutions, include my favourite 
PostgreSQL.

-- 
Milos Prudek