CREATE OR REPLACE
FUNCTION PERSON_ID
(
  searchString IN VARCHAR2
) RETURN NUMBER IS
id person.person%TYPE;
too_many EXCEPTION;
not_found EXCEPTION;
CURSOR get_person_id IS
SELECT person FROM person WHERE name LIKE searchString;
CURSOR get_person_id2 IS
SELECT person FROM person WHERE realname LIKE searchString;
BEGIN
  OPEN get_person_id;
  IF get_person_id%NOTFOUND THEN
    OPEN get_person_id2;
    IF get_person_id%NOTFOUND THEN
      RAISE not_found;
    ELSIF get_person_id%ROWCOUNT > 1 THEN
      RAISE too_many;
    ELSE
      FETCH get_person_id2 INTO id;
    END IF;
  ELSIF get_person_id%ROWCOUNT > 1 THEN
    RAISE too_many;
  ELSE
    FETCH get_person_id INTO id;
  END IF;
  RETURN id;
EXCEPTION
WHEN too_many THEN
DBMS_OUTPUT.put_line('Fehler: Es wurden mehrere passende Einträge gefunden.');
WHEN not_found THEN
DBMS_OUTPUT.put_line('Fehler: Es wurde kein passender Eintrag gefunden.');
END PERSON_ID;