In your table schema class, create a "private" column accessor with:
- __PACKAGE__->add_columns(my_common => { accessor => '_hidden_my_column' });
+ __PACKAGE__->add_columns(my_column => { accessor => '_hidden_my_column' });
Then, in the same class, implement a subroutine called "my_column" that
fetches the real value and does the formatting you want.