create or replace procedure scheduledelete
is 
  cursor c_tempo is 
    select * 
      from retentionschedule 
     where disposalaction = 'Delete' 
       and disposaldate < sysdate;
 
  cursor c_tables is
    select distinct tablename 
      from retentionschedule 
     where disposalaction = 'Delete' 
       and disposaldate < sysdate;
 
  v_sql  varchar2(4000);
begin 
  for v_tempo in c_tempo loop
 
    execute immediate 
      'update CRM.' || v_tempo.tablename || 
      ' set ' || v_tempo.fieldname || ' = null' ||
      ' where customerid = :customerid' using v_tempo.customerid;
 
    delete 
      from retentionschedule
     where id = v_tempo.id
       and customerid = v_tempo.customerid
       and disposaldate = v_tempo.disposaldate
       and tablename = v_tempo.tablename
       and fieldname = v_tempo.fieldname
       and disposalaction = v_tempo.disposalaction; 
 
  end loop;
 
  for v_tables in c_tables loop
 
    v_sql := null;
     
    for c in (select column_name
                from user_tab_columns
               where table_name = v_tables.tablename
                 and nullable = 'Y') loop
 
      v_sql := v_sql || ' and ' || c.column_name || ' is null';
      
    end loop;
    
    if v_sql is not null then
 
      execute immediate
        'delete from ' || v_tables.tablename ||
        ' where ' || ltrim(v_sql, ' and ');
        
    end if;
    
  end loop;      
 
  commit;
 
end scheduledelete;
/

for c in (select column_name from <b>all</b>_tab_columns where <b>owner = 'CRM'</b> and ...