Question

According to documents, non-atomic refresh of a materialized view uses truncate instead of delete in complete refresh. Is there any way to say oracle to use truncate instead of delete when creating a materialized view ?

Answer 1

There’s no method that I’m aware of – you have to explicitly call dbms_mview.refresh with atomic => false:

begin
  dbms_mview.refresh( 'EMP_MV' , atomic_refresh => FALSE );
end;

EDIT: Unless you’re using Oracle 9.2 or earlier – these versions perform a non-atomic refresh by default.