Re: [gnome-db] trigger support or simulation with libgda ?

[Rodrigo Moya <rodrigo gnome-db org>]

On Sun, 2005-04-17 at 13:24 +0200, reinecke fox gmx net wrote:
> > > 
> > > In LibGda 1.3.1 GdaDataModel is a GObject, then you
> > > can associate a callback to any event. The events know
> > > sopported are:
> > > 
> > > changed
> > > row_inserted
> > > row_updated
> > > row_removed
> > > column_inserted
> > > column_updated
> > > column_removed
> > > begin_update
> > > cancel_update
> > > commit_update
> > 
> > This would not work to be notified of a table's contents change as the
> > data model notifies of changes made to its own contents (defined in
> > any way you want).
> > 
> > Postgres has the notification system which allows to be notified of a
> > named condition which has to be "emitted" by the NOTIFY command. The
> > condition then needs to be emitted by a trigger. This is not really
> > portable...
> > 
> > Libgda has support for notifiction propagation through the
> > "event-notification" signal of the GdaClient object. However for now
> > the only events to be notified do not include table content change.
> > More work would be required to add such support, but it is doable.
> > 
> > Vivien
> 
> 
> however it could be possible to use an event of the GdaDataModel object
> by polling a source-table to fill the GdaDataModel contents. A change
> in the table produces an update in GdaDataModel (by polling) what provokes 
> the event-execution. A not very nice workaround, I know - but maybe usable. 
> I'm not sure... Can anyone affirm this idea?
> 
> a general note to this topic:
> Do you think the discussed feature is interesting enough to implement to libgda?
> For a long time, I'm looking for a database abstraction layer supporting any
> content change notification - without any success :-(
> 
yes, it is very interesting, so if anyone wants to implement it, just go
ahead.
-- 
Rodrigo Moya <rodrigo gnome-db org>