postgresql triggers to update GUI?
Gerhard Häring
gh_pythonlist at gmx.de
Mon Nov 26 23:35:26 EST 2001
On Mon, Nov 26, 2001 at 02:52:39PM -0500, Robert Nikander wrote:
> Hi,
>
> I am writing a python program that uses a postgresql db backend. I would
> like to update the gui whenever a change in certain tables occurs, so it
> would be nice to use triggers rather than generating the 'events' when I
> update the db. That way I get cascading changes. Does anyone know of a
> python module that supports postresql triggers? ie: you can create a
> trigger that calls a python function? Is there another solution here
> that I am missing?
Hmm. I think you could use PostgreSQL's notification mechanism for this.
pyPgSQL does support PostgreSQL notifications (look into the demo2a.py and
demo2b.py files in the examples/ directory). The URL is http://pypgsql.sf.net/
I think you could have your trigger send a PostgreSQL notification and have the
client side select.poll() or select.select() for the notification. The above
mentioned examples show how to do this.
Gerhard
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