Hello Zopistas, This is a little off-topic but I had no other place to ask. I'm using Zope & PostgreSQL together on a intranet accounting system (BTW, it's Open Source and I'll post it soon.) Anyway, I have several tables related by ids (keys), and I have to create these keys by myself. They're of the form YYYYMMDDCCCCCC (Y: year, M: month, D: day, C: a consecutive transaction number that I must generate) and they must be unique. Of course, from day to day, these numbers are guaranteed to be unique, my problem relies on Intra-Day-Uniqueness (TM). How could I generate the consecutive part? Unfortunately, I can't use the underlaying RDBMS auto-numbering or auto-sequence feature. Since the keys _must_ conform to the above scheme. All I can count on is on the database rows (an ideal solution would be conceptually independent of both Zope and PostgreSQL). I was even thinking of having a separate table having the last transaction number stored in a single row which would be updated by locking the table... just a thought. Of course, this would be a multiuser environment. Any one? Best regards and TIA, -- [ c a r l o s c a r n e r o ] [ r t v c o m e r c i a l ] [ t e x e l @ r t v c . c o m . c u ]