The actual conversion is not what I'm trying to get done. What I want is for the conversion to be done automatically at a level much lower than I care to fiddle with.

Corion's Class::DBI trigger idea is probably the best, but I'd like to be able to do it at the DBI level if possible, since the DBH should really be losslessly relaying data I send to and from it and Class::DBI should not be touch that.