On 17 October 2012 18:46, Greg Stark <stark@mit.edu> wrote:
> I would suggest something like
>
> Warning: RULES are tricky to use correctly. They rewrite the original
> query into a new query before it is run and it is very hard to
> correctly anticipate and rewrite every possible input query into the
> desired result. There are also unexpected interactions with other
> components when RULES do something unexpected such as rewrite a single
> query to return two result sets.
>
> For most applications it's much simpler and more predictable to use
> TRIGGERs. ROW level triggers are evaluated for each row the original
> query is about to process (or has just finished processing) and this
> makes them much easier to follow. Statement level TRIGGERs can be used
> for audit logs and similar operations which need to run once per
> statement.
I like this very much. Thank you.
-- Simon Riggs http://www.2ndQuadrant.com/PostgreSQL Development, 24x7 Support, Training & Services
