Hello,
Thanks for posting, and its a valid request.
Currently while UPDATE we are SETting all column values, and use the PK column in WHERE clause if its present, otherwise use all columns in WHERE clause.
We should SET only column(s) those are edited, in UPDATE clause .
I added this to issue tracker
http://code.google.com/p/sqlyog/issues/detail?id=1063
We will look into this issue after 8.1 GA released and update the status here(probably next week).
Regards
Nithin