RDBMS comparison tool

Hi All,
   Whilst working on another project it made sense to write a tool for 
comparing the various RDBMSs. I'm talking about the database management 
systems themselves, not databases within them. So far I've done parts 
that use $dbh->type_info_all() to compare what types SQL Server, 
Postgres, Oracle and MySQL have available and their details. Generating 
reports like:
http://cosmicperl.com/rdbms/compare_types.html
http://cosmicperl.com/rdbms/compare_type_details.html

I'm not yet sure as to whether the mapping from the RDBMSs local sql 
type to the ones the DBI recognises is done by the DBD driver, or 
whether this is already predetermined by the RDBMS...

Let me know if this isn't interesting to you all and I'll keep it off list.

Lyle