SQL database

Question

 Create a trigger named Products_UPDATE that checks the new value for the DiscountPercent column of the Products table. This trigger should raise an appropriate error if the discount percent is greater than 100 or less than 0. If the new discount percent is between 0 and 1, this trigger should modify the new discount percent by multiplying it by 100. That way, a discount percent of .2 becomes 20. Test this trigger with the following UPDATE Products SET DiscountPercent = .25 WHERE ProductID = 1; Check to make sure the DiscountPercent is 25 with a SELECT statement.

Answer 1

CREATE OR REPLACE TRIGGER Products_UPDATE ON PRODUCTS

BEFORE UPDATE

ON PRODUCTS

FOR EACH ROW

BEGIN

IF UPDATING THEN

IF (:NEW.DiscountPercent < 0 OR :NEW.DiscoutPercent > 100

RAISE_APPLICATION_ERROR (-10000, 'Discount Percent is invalid - must be between 0 and 100.');

ELSIF (:NEW.DiscountPercent BETWEEN 0 AND 1 THEN

:NEW.DiscountPercent := :NEW.DiscountPercent * 100;

END IF;

END IF;

END;

SELECT * FROM PRODUCTS WHERE CategoryID = 1;