Re: what are rules for? - Mailing list pgsql-general

From Michael Shulman
Subject Re: what are rules for?
Date
Msg-id c3f821000806261047x19173565ne37ee15618c289a4@mail.gmail.com
Whole thread Raw
In response to Re: what are rules for?  (Dean Rasheed <dean_rasheed@hotmail.com>)
Responses Re: what are rules for?  (Dean Rasheed <dean_rasheed@hotmail.com>)
List pgsql-general
On Thu, Jun 26, 2008 at 12:11 PM, Dean Rasheed <dean_rasheed@hotmail.com> wrote:
> This can almost be implemented in PostgreSQL right now, using a rule of
> the form "... do instead select trigger_fn()" - except, as you point out, the
> caller won't know how many rows were actually updated. As far as the
> top-level query knows, it didn't update anything, which will break some
> (most?) clients. Apart from that, this does actually work!

Yeah, I actually thought of that.  But as you point out, many clients
would get confused.  Someone pointed out in an earlier thread that a
way to fix this, for updates on a multi-table view (where most of the
complication lies), is to write a "trigger" function that updates all
the constituent tables except for one, and then write a rule that
calls that function and then updates the one remaining table itself.
This seems to work okay although I have not tested it with many
clients.

Mike

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