Will updating Mac OS affect my Windows/Bootcamp partition? On Macbook Air, I have OSX 10.9.4 and it allows me to update to Yosemite, will this affect the Windows 7 partition that I installed using Bootcamp ?

Edit: seems to work ok for one windows/bootcamp partition, but an additional windows partition will cause problems. I will add a detailed answer to my own question.
Unless something goes wrong during install: no. But it's always smart to have a backup.