ZODB (and OODB) question

[chris]

I am writing an application using zope and I am saving my objects
(customers, transactions, etc.) in the ZODB rather than using a RDBMS
such as MySQL.

In a RDBMS I can easily run batch update jobs, for example, running
nightly jobs to  update customer's status depending on whether or not
the customer pays an invoice on-time.

In the RDBMS, I would perform something like the following to do this:

UPDATE customer SET status = 'stopped' WHERE ...

How can I perform the same update using an OODB?  The only way I can
think of doing this at the moment is to traverse through each and
every customer object and set their status individually depending on
my criteria - not very efficient!

I would appreciate any help on this, even if I just get pointed to
relevant documentation that would help me.

Thanks in advance,
Chris Snow