Portable schema?

I'm trying to set up a schema (ie. SQL script) that I can use with both Oracle and Informix. Constraint definitions seem to be the where the most syntactic differences are. I've tried to use the C preprocessor to conditionalize a lot of the code but I've gotten to where there's more conditional code than shared code. It's pretty ugly. Is this a lost cause? Does anyone know a good way to do this? TIA! Roger Tomas AG Communication Systems