set serveroutput on

declare
  v_count         number;
  v_object        varchar2(20);
  v_owner         varchar2(20);

begin
  select count(*) 
    into v_count
    from dba_objects
   where status   <> 'VALID';

  dbms_output.put_line (v_count || ' invalide Objekte gefunden');

exception
   when others then
      dbms_output.put_line ('Fehler: ' || SQLCODE);

end;
/



declare
  v_owner         varchar2(20);
  v_object        varchar2(20);

begin
  select owner,   object_name 
    into v_owner, v_object
    from dba_objects
   where owner       = 'SCOTT'
     and object_name = 'EMP';

  dbms_output.put_line ('Objekt vorhanden');

exception
   when others then
      dbms_output.put_line ('Objekt NICHT vorhanden');

end;
/