Hi

> Is it possible to write an Insert Trigger that test for the existence of

the pk and then make an Update of the data if it allready exist?

Just a new idea:

What about deleting the old row, in a "BEFORE INSERT" trigger?
Insertion would stay insertion. This should work.

BUT remember: Foreign key should not be involved here!
(Because temporary deleting the original row to enable the insert would
cause ON DELETE actions.)

Regards,
Steffen