[web2py] common fields shared by different tables

[Manuele Pesenti]

what's the best way to define a minimal list of fields that I want to 
repluicate in some tables?
I thought to define a table but as I need it only to be used inside 
other tables I don't need it's really created in my db... and I don't 
want it... is it possible?

thanks a lot
        Manuele