Kelly,
> Is there a test to see if a call to currval will fail? I would like
> to
> call nextval one time per session inside a trigger. I am working on
> other solutions, but I searched the docs and didn't find what I was
> looking for.
You could do "select last_value from <sequence name>" instead.
However, I'm not sure that that method of getting the currval is
session-protected in the way that currval is.
-Josh Berkus