SHOW ERRORS;

CREATE OR REPLACE TRIGGER libloan_zero
BEFORE INSERT OR UPDATE ON bookloan
FOR EACH ROW
DECLARE

thisfirstname VARCHAR2(25);
thislastname VARCHAR2(25);
thisbook_title VARCHAR2(25);
thislocation VARCHAR2(25);
 
BEGIN
 
IF :NEW.evaluation =0 THEN
          SELECT customer.firstname,customer.surname,book.title,bookcopy.location
          INTO thisfirstname, thissurname, thisbook_title, thislocation
          FROM customer, bookcopy, book
          WHERE customer.customer_id = :new.customer_id
AND bookcopy.copy_id = :new.copy_id
AND book.book_id = copy.book_id;
 
INSERT INTO evaluation VALUES (thisfirstname,thislastname,thistitle,:NEW.hire_date, thislocation, :NEW.evaluation);
END IF;
END;

SHOW ERRORS;
CREATE OR REPLACE TRIGGER libloan_december 
BEFORE INSERT OR UPDATE ON bookloan 
FOR EACH ROW
DECLARE
out_of_range EXCEPTION; 
thislocation VARCHAR2(20);
BEGIN
SELECT location INTO thislocation
FROM bookcopy WHERE copy_id = :new.copy_id;
IF thislocation = 'London' THEN 
IF TO_CHAR(:new.hire_date , 'MONTH') = 'DECEMBER ' 
THEN RAISE out _of_range; 
END IF; 
END IF; 
EXCEPTION 
WHEN out_of_range THEN RAISE_APPLICATION_ ERROR(-20100, 'No books can be hired in London during December'); end;

RAISE_APPLICATION_ ERROR