Question

I found a trigger in our Oracle Database

create or replace trigger pii_user_activation_trigger
  before insert on pii_user_activation
  for each row
begin
  select seq_pii_user_activation.nextval 
    into :new.id 
    from dual;
end;

I don’t want the trigger to automatically generate the id each time a row is inserted. How can I modify the trigger so that it only generates a new id if the INSERT statement does not provide a value?

Answer 1

It sounds like you just want

create or replace trigger pii_user_activation_trigger
  before insert on pii_user_activation
  for each row
begin
  IF( :new.id IS NULL )
  THEN
    select seq_pii_user_activation.nextval 
      into :new.id 
      from dual;
  END IF;
end;

This makes the generally reasonable assumption that there is no non-NULL default value specified for the column.