Scaffolding again after new columns in table


I am a newbie to RoR, and wanted to know how-to go about adding a new
column to a table. Once if I add the table, then is it necessary to
scaffold again, and how to be sure that I do not regenerate my
controllers, views and model defined earlier. I am just attempting to
add a new column to the table in order to store additional data about
an item, and show that additional data along with the normal view (of
the item earlier)

Can somebody please help me on this. I know this is a very trivial
thing, but I am afraid if I regenerate my model, view, controller

Thanks and regards

scaffolding is no mandatory step
if you add a new column, you can as easy add the entry for it in
the existing form
most people i know never use scaffolding anyway, since with a
bit of experience you can write those few lines fast enough