Missing fields when using scaffold

Hey Everyone,

When using a dynamic scaffold (i.e. putting "scaffold :object" in a
controller) to build my app, I noticed that input fields were missing
for some of the object's columns in my 'new object' form.

Using a real scaffold did not help.

Is there a certain set of conditions under which a scaffold will not
generate fields for ALL of an object table's columns? This is
baffling me... I thought (and have seen many times in the past) that
all columns get corresponding fields on scaffolded forms.

Thanks very much for any insight you can provide.