我想创建一个触发器,通过计算2个值来更新行并更新第三个值:
CREATE TABLE Customers (
Cust_ID INTEGER PRIMARY KEY,
Dates TIMESTAMP WITH LOCAL TIME ZONE,
Quantity dec(7,2) NOT NULL,
Price_per_item dec(7,2) NOT NULL,
Total_price dec(7,2)
);
我做到了:
CREATE OR REPLACE TRIGGER cust_after_insert AFTER INSERT
ON Customers
FOR EACH ROW
BEGIN
UPDATE Customers
SET
DATES = CURRENT_TIMESTAMP,
Total_price = Quantity * Price_per_item;
END;
我遇到了一些我尝试同时查看和编辑表格的错误。
我也试过这个:
CREATE SEQUENCE cust_Seq START WITH 1 INCREMENT BY 1;
CREATE OR REPLACE TRIGGER cust_trig BEFORE INSERT ON Customers
FOR EACH ROW
BEGIN
SELECT cust_Seq.nextval INTO :new.Fuel_ID FROM dual;
SELECT CURRENT_TIMESTAMP INTO :new.DATES FROM dual;
SELECT Quantity * Price_per_item INTO :new.Total_price FROM dual;
END;
/
我更喜欢第二个选项,如果UPDATE也会出现,我会需要一些东西。
答案 0 :(得分:0)
第二种方法是正确的方向,但需要进行一些调整以处理Total_price
计算并处理update
:
CREATE SEQUENCE cust_Seq START WITH 1 INCREMENT BY 1;
CREATE OR REPLACE TRIGGER cust_trig BEFORE INSERT OR UPDATE ON Customers
FOR EACH ROW
BEGIN
IF INSERTING THEN
SELECT cust_Seq.nextval INTO :new.Fuel_ID FROM dual;
SELECT CURRENT_TIMESTAMP INTO :new.DATES FROM dual;
END IF;
:new.Total_price := :new.Quantity * :new.Price_per_item;
END;
/