我如何创建触发器我有我的代码，但它有一个错误

Question

create or replace TRIGGER "CARAVAN"
    before insert or update ON caravan
        FOR EACH ROW DECLARE cara_no number;
            BEGIN
                if inserting then
                    if :new.caravan_no is null then
                       select caravan.nextval into cara_no from dual;   
                       :new.caravan := cara_no;
                    end if;
                    if :new.tags is not null then
                       :new.tags := caravan_new.tags_cleaner(:new.tags);
                    end if;
                end if;
                caravan_new.tag_sync(
                    p_new_tags => :new.tags,
                    p_old_tags => :old.tags,
                    p_content_type => 'CUSTOMER',
                    p_content_id => :new.caravan_no );
            END;

这是我的代码中的两个错误

ORA-24344: success with compilation error   



PLS-00103: Encountered the symbol "CREATE" when expecting one of the following: 
( begin case declare exit for goto if loop mod null pragma 
  raise return select update while with <an identifier>