It would be great if Postgres connection class provided high-level notifying system, based on Postgres NOTIFY.
It could look like:
template<T> WSignal<dbo::ptr<T> > listen(); template<T> void notify(dbo::ptr<T>);
This can be used to notify other sessions (inside or outside this process or PC).
Applications seem to use not sqlite3, but postgres in production, and this notifying system seems useful for production applications.
Maybe these methods should be methods of Session or WServer...
This idea was inspired by WServer::post, which can be used for Dbo object update notifying.