On Wed, Aug 11, 2004 at 20:50:28 -0500, David Stanaway <david@stanaway.net> wrote:
>
> I had thought about that, but this is a simpler case of what I need to
> do. The operations for each column in the update are dependent on the
> current and new values of each row being merged.
>
> Currently I am doing this with a cursor which is very slow! How about a
> trigger on update? Or would this suffer the same behavior that I am
> seeing with UPDATE FROM with a 1-many join?
There is a good chance that triggers would be faster since tablea seems
to reallly be a materialized view of an aggregate over tableb and doing
a delta calculation when a row changes is going to be faster than recalculating
the aggregate from scratch.
You won't have the same problem if you use a trigger as when you were
trying to calculate an aggregate using UPDATE.
