Dag H. Wanvik wrote: > Hi, > > Andreas> > 2) Applications use the FOR UPDATE clause to control locking for > Andreas> > future updates with read only ResultSets. > Andreas> > > Andreas> > Andreas> Note currently it throws an exception if the statement is not > updatable > Andreas> i.e contains a join or order by. > > I guess what you mean here is that the FOR UPDATE is not in general > available as a means for locking for future updates. > > To Dan's point, my tests indicate that the current Derby > implementation for forward-only updatable result sets only sets a row > update lock while on the current row.
I think that's only true for read committed isolation level, in higher levels the update lock will be there until end of transaction. So I guess this use is only useful with those isolation levels. Dan.
