Wich is an excellent idea. So I refactored the complete trigger using your idea.
CREATE TRIGGER C_CHECK_DATA BEFORE INSERT ON COMPANY
BEGIN
SELECT SF(0)
WHERE NEW.AGE < 16;
SELECT SF(1)
WHERE LENGTH(NEW.ADDRESS) == 0;
INSERT INTO AUDIT(EMP_ID, NOTICE)
VALUES (
NEW.ID,
(SELECT CASE 1
WHEN (FS(0) AND FS(1))
THEN NEW.NAME || 'is too young and has an invalid address FS(0)→ ' || FS(0) || ' FS(1)→ ' || FS(1)
WHEN (FS(0) AND FC(1))
THEN NEW.NAME || ' is too young to be an employee. FS(0)→ ' || FS(0) || ' FS(1)→ ' || FS(1)
WHEN (FC(0) AND FS(1))
THEN NEW.NAME || ' has an invalid address. FS(0)→ ' || FS(0) || ' FS(1)→ ' || FS(1)
ELSE 'OK. FS(0)→ ' || FS(0) || ' FS(1)→ ' || FS(1)
END)
);
SELECT CF(0), CF(1);
END;