Hello, I have a probably simple question, but got different opinions on the matter, and I'm seriously in need of a quick answer. I need to make a ZSQL method that inserts data in a table this way: 1) first, generate a new ID with something like SELECT MAX(ID)+1 AS my_id FROM ... (using a sequence is not an option for me for various reasons) 2) then, INSERT with the ID previously generated ( is INSERT INTO ... VALUES (<dtml-var my_id>.... the right way to do this ?) 3) display my_id to the user for future reference. First, I'm not sure how to do 3) : how do I pass my_id back to the original DTML document (which calls the ZSQL method with dtml-call) ? Also (main question), is there something particular to do to ensure SELECT+INSERT is done in an atomic way that avoids concurrency problems ? I know Zope starts and ends transactions with HTTP requests, but I'm not sure this implies the kind of read locking I need. thanks a lot! PS: please cc any answers.