I think that using a loop (especially to iterate through a cursor) might be a good idea here, so I'd agree with mom ... BUT ... you don't want to commit every loop iteration if you're retrieving one row per iteration.  That would kill your performance (I could go into painful detail here, but it works better on a whiteboard).  I'm pretty sure that mom means the technique where your where clause allows the update of a bunch of rows every loop iteration, so that each commit also handles a bunch of rows.  But I thought it would be worth mentioning explicitly, because (ouch!) issuing a commit on each row update can just destroy your throughput.

Cheers,

Chris