There seems to be some strange responses coming in to this.
As far as I can tell the problem is relatively simple:

> My trigger looks like this:

> CREATE OR ALTER TRIGGER JOB_AIU3 FOR JOB
> ACTIVE AFTER INSERT OR UPDATE POSITION 3

^^^^^^^^^^^^^^^^^^^^^^
[...]

> /* UPDATE JOB WITH ALLOC INITIALS */
> NEW.tech_alloc_display = :V_ALLOC;

It's an "after" trigger so it's too late to try and change
one of the New* values (otherwise it wouldn't actually be
after would it).

Change this to a before trigger and it should all work I think.

--
Geoff Worboys
Telesis Computing