will this update cause an index rebuild

Hi All

I have a table with 3 cols (c1,c2,c3)
with primary key index on c1.

now when i update a value for a row in the c1 column the index will rebuild (correct me if i m wrong)
Now say i dont update the pk col (c1) value but i update c2 and c3 . In this will it cause an index to rebuild

Rgrds

The index will be modified if any of the indexed values changes. This isn't a "rebuild", it's just a change.