Re: [sqlite] Callback when table contents have changed

[Jason Jobe]

Using a trigger is exactly what I have done. It works great and you get 
to easily control the parameters of event.

Just register your user-defined function and create a trigger thusly.
create trigger log_report after
    insert on logEvent
    for each row
    begin
        select appLogCallback ('logEvent', new.pid, new.key, new.title) 
from logEvent where pid = new.pid;
    end;

- jason
On Apr 19, 2005, at 4:48 AM, Ulrik Petersen wrote:
Hi Frank,
F.W.A. van Leeuwen wrote:
I've asked this two weeks ago but no reply yet...
I've got one application that writes to the database, and one that 
reads from it.  When a table in the database has changed, the reading 
application needs to know that.  Of course I can send a signal from 
the writer to the reader app, but if the database would have a means 
for that, I think it would be more elegant (not directly coupling the 
writer and the reader).  So it would be nice if a C application could 
subscribe to "table changed" events.  I don't think it is currently 
possible with SQLite, is it?

Frank.
Isn't that what triggers are for?  Perhaps you could couple a trigger 
with a user-defined function.

HTH
Ulrik
--
Ulrik Petersen, MA, B.Sc.
University of Aalborg, Denmark