Update Cascade trigger

Hi, I don't think this can be done, but I wonder if anybody has a workable solution. I have four tables with a parent / child relationship, with the unique key to each table being made in part from the key to the parent. table A ---> table B ---> table C ----> table D with table A being the parent to table B table B being the parent to table C table C being the parent to table D If a value in table A needs to be changed all the associated rows in table B, C and D also need to be changed, but obviously the parent/child constraints will not allow the change to happen, because the rows in B would be referencing the 'old' value in table A which would invalidate the constraint etc. What I would like is some way to cascade the update before the constraint rule takes hold, but I don't think this is possible. One way would be to drop all constraints, write SQL to do all the updates and then reapply the constraints, which is a bit messy. Can anyone supply a better method? Thanks in advance -- Peter __________________________________ Peter Marley DBA, Acco UK Ltd Tel: +44 (0)1296 397444 ext. 4098 Fax: +44 (0)1296 311019 email: peter.marley@acco-uk.co.uk