Stephen Cook wrote:
> I am curious (coming from a MS SQL Server background, I just started
> playing with PostgreSQL recently).
>
> What type of situation would warrant a statement-level trigger that
> can't access the old and new values? Without that access, isn't the
> only information you get is the fact that an operation occurred on the
> table? Or am I missing something?
>
> -- Stephen
What about this. Suppose you have this table "planets":
planet_name | star_id|....
There is a lot of stars, right? And if a very common query involves a
"select planet_name, count(*) from planets group by star_id"....Well, if
there is 1.000.000.000 of galaxies, and 1.000.000.000.000 of stars per
galaxy...Thats a lot of planets to count!!! So maybe you want a helper
table who maintains such of subtotals.
Well, each time you discover a new galaxy, insert every planet in the
monster table, and *after* all the inserts, run a trigger for updating
the helper table.
Cheers.
Gerardo
