????

Sorry, but that is my most accurate answer. You have a simple view including
the primary key of a table, without any join whatsoever (and as far as I can
see, not even a limiting where clause). I simply cannot understand why
selecting from this view should prevent you from using the table's primary
key in a plan when using the table directly allows it. And I guess you have
already checked that you do not have any duplicate indexes (i.e. only the
primary key on NUMMER, not any additional ascending indexes for it)

Time to leave this issue for the real experts and hope that Helen soon will
be installed in her new home...

Set
-beaten by a simple select