Create or replace trigger

Question

hi i want to create trigger . when insert a row on table , it returns new value and old value . I have many tables and columns . i should to use :new.columntitle and :old.columntitle .Columntitle is refere to name of column in table . but sql developer is not accept it and show this error : BAD BIND VARIABLE 'NEW.COLUMNTITLE' .My code is this :
Create or replace TRIGGER hr.departments_before_insert   
  before insert       on HR.departments 
   for each row
   DECLARE
      columnid number ;
     columnval number ;
     columntitle varchar2(4000);
     cursor c2 is
     select id,tableid from hr.columns where tableid = 1 ;
      tablesid number ;
      tablenames varchar2(4000);
      cursor c1 is
      select id , title from hr.tables where id = 1;
                BEGIN
                open c1;  
                       loop
                          fetch c1 into tablesid , tablenames;
                              EXIT WHEN C1%NOTFOUND;    
                               for rec in c2
                                        loop
                                             select substr(title,instr(title,'.',-1,1)+1) into columntitle  from hr.columns where id = rec.id ;
                                             dbms_output.put_line(:new.columntitle); -- in this line the eroor occured  : error = " bad bind variable 'new.columntitle' "
                                         end loop;
                         end loop;
                close c1;    
                 end;
-- in loop columntitle=deparment _id and department_name ; when i replace columntitle with department _id in :new , code is work ...
thanks                                                                                                                                                         

Answer 1

You have no choice but to specifically list the column names.
If you really have "too many columns", that would tend to imply that you have improperly normalized your schema.  Perhaps you need to rethink the data model.
If the real problem is that you want to generate similar triggers for a large number of different tables, you could write a PL/SQL block that generates the CREATE TRIGGER statement for each table and use EXECUTE IMMEDIATE to run those statements for each table.  Using dynamic SQL like this significantly complicates the complexity of building the trigger.  This may be balanced out, though, by the fact that you only have to write it once rather than writing separate triggers for each table.
Justin