Change m to cm

Hi
I have upload all the products through csv file
All the products have measurement unit as default in m. How to change all 512 products from m to cm?
Is it possible with csv file and how?

Also can i add products more than one categories through csv files?

Thanks

ok i fix it
fo anyone to know create a csv file with column product_code and column product_dimension_unit
Add in cells of product_dimension_unit the unit for example cm.
Upload it and its ok