But you will be violating the terms of any credit card usage if you do so.
Credit card numbers can't be legally stored on any SHARED hosting site, because of the danger that some other account user on the site could hack into your database. They can only be stored in fully secured systems, which clearly a MySQL DB on Yahoo is not.
An optimist sees the glass as half full.
A pessimist sees the glass as half empty.
A realist drinks it no matter how much there is.