我有一个小组项目,我们正在其中创建一个购物车应用程序。我得到了一些反馈并将其修复,将其变成带有游标的过程。但是,我们仍然遇到我不知道如何解决的错误,例如尝试将null值放入不能为null的表列中。我不知道为什么它认为我正在尝试输入空值。我们的项目明天到期,所以请帮忙!
起初我尝试将其作为触发器,但是它无法正常工作,因此建议将其转换为带有游标的过程,所以我做到了。
create or replace PROCEDURE CANCELCART (arg_cart_id IN number)
IS
ws_prod_id number;
ws_item_quantity_in_cart number;
ws_cart_id number;
ws_cart_status char;
cursor cancel IS
select item_product_id, item_quantity_in_cart
FROM sc_items i
WHERE item_cart_id = arg_cart_id
group by item_product_id;
alreadycancelled exception;
BEGIN
select max(cart_id) into ws_cart_id
from sc_cart
where arg_cart_id = cart_id;
/*cart check*/
select max(cart_status) into ws_cart_status
from sc_cart
where arg_cart_id = cart_id;
if ws_cart_id is null
then raise alreadycancelled;
end if;
open cancel;
LOOP
fetch cancel into ws_prod_id, ws_item_quantity_in_cart;
UPDATE sc_product p SET prod_quan_avail = prod_quan_avail + ws_quantity_in_cart,
prod_quan_sold = prod_quan_sold - ws_quantity_in_cart
WHERE prod_id = ws_prod_id;
DELETE FROM sc_items i WHERE i.item_cart_id = arg_cart_id;
END LOOP;
close cancel;
DELETE FROM sc_cart c WHERE c.cart_id = arg_cart_id;
EXCEPTION
when alreadycancelled
then raise_application_error(-20400, 'Cart does not exist');
END;
我需要此代码来取消购物车,并将所有项目数量返回到原始库存。
答案 0 :(得分:1)
除了使用数据类型定义ws_quantity_in_cart
变量,并为其他类型的异常添加了比已包含的ORA-20400
更多的处理之外,您的代码块没有太多缺少的部分
CREATE OR REPLACE PROCEDURE CANCELCART( arg_cart_id sc_cart.cart_id%type ) IS
ws_prod_id sc_product.prod_id%type;
ws_item_quantity_in_cart sc_product.prod_quan_avail%type;
ws_cart_id sc_cart.cart_id%type;
ws_cart_status sc_cart.cart_status%type;
ws_quantity_in_cart sc_product.prod_quan_sold%type;
cursor cancel IS
select item_product_id, item_quantity_in_cart
from sc_items i
where item_cart_id = arg_cart_id
group by item_product_id;
alreadycancelled exception;
BEGIN
select max(cart_id)
into ws_cart_id
from sc_cart
where arg_cart_id = cart_id;
/*cart check*/
select max(cart_status)
into ws_cart_status
from sc_cart
where arg_cart_id = cart_id;
if ws_cart_id is null
then raise alreadycancelled;
end if;
open cancel;
loop
fetch cancel into ws_prod_id, ws_item_quantity_in_cart;
update sc_product p
set prod_quan_avail = prod_quan_avail + ws_quantity_in_cart,
prod_quan_sold = prod_quan_sold - ws_quantity_in_cart
where prod_id = ws_prod_id;
delete sc_items i where i.item_cart_id = arg_cart_id;
end loop;
close cancel;
delete sc_cart c where c.cart_id = arg_cart_id;
exception when alreadycancelled then raise_application_error(-20400, 'Cart does not exist');
when others then raise_application_error(SQLCODE,SQLERRM);
END;
优选使用<table_name>.<column_name>.%type
使用列的原始数据类型来定义变量的数据类型,并且永远不要使用类型为char
的定长字符串类型的变量,而应使用varchar2
。 / p>