[Zope-dev] unique rec id for Gadfly?

Dear Zope-masters, How do I generate a unique record id for a newly inserted record for Gadfly? I have the following code: <dtml-call "manage_changeProperties(last_rid=last_rid + 1)"> <dtml-let rid=last_rid> <dtml-call insert_new_record> </dtml-let> where last_rid is a property defined in the folder. However, rid does not get into the zsql method. BTW, how do I test if the insert operation success? Rgs, Kent Sin