Ограничение на количество (триггер)

CREATE TRIGGER kolvo_p
FOR c_preparat
BEFORE INSERT AS
DECLARE VARIABLE k;
--numb_c=new.n_c;
k=SELECT COUNT (n_prepar) FROM c_preparat WHERE n_c=NEW.n_c;
IF (k=5)
THEN EXCEPTION RAISE_TOO_HIGH;

CREATE TRIGGER kolvo_p
FOR c_preparat
BEFORE INSERT AS
DECLARE VARIABLE k;
--numb_c=new.n_c;
BEGIN
k=(SELECT COUNT (n_prepar) FROM c_preparat WHERE n_c=NEW.n_c);
IF (k=5)
THEN EXCEPTION RAISE_TOO_HIGH;
END

DECLARE VARIABLE k INT;

CREATE TRIGGER kolvo_p
FOR c_preparat
BEFORE INSERT AS
BEGIN
  IF ((SELECT COUNT(n_prepar) FROM c_preparat WHERE n_c=NEW.n_c)>=5) THEN
    EXCEPTION RAISE_TOO_HIGH;
END

CREATE TRIGGER kolvo_p
FOR c_preparat
BEFORE INSERT AS
DECLARE VARIABLE k INT;
BEGIN
  SELECT COUNT(n_prepar) FROM c_preparat WHERE n_c=NEW.n_c INTO :k;
  IF (k>=5) THEN 
    EXCEPTION RAISE_TOO_HIGH;
END

SET TERM !! ;