接收contract_no和item_no值，在inventory表中查找，如果产品：?
已发货，在arrival_date中赋值为今天后的7天?
已订货，在arrival_date中赋值为今天后的一个月?
既无订货又无发货，则在arrival_date中赋值为今天后的两个月，?
并在order表中增加一条新的订单记录。?

product_status的列值为'shipped'和'ordered'?
inventory:?
product_id?number(6)?
product_description?char(30)?
product_status?char(20)?
std_shipping_qty?number(3)?
contract_item:?
product_id number(6)?
contract_no?number(12)?
item_no?number(6)?
arrival_date?date?
order:?
order_id?number(6)?
product_id?number(6)?
qty?number(3)?

 
代码如下:
declare
i_product_id inventory.product_id%type;
i_product_description inventory.product_description%type;
i_product_status inventory.product_status%type;
i_std_shipping_qty inventory.std_shipping_qty%type;
begin
//sql语句，将查询出来的值放到定义的变量中
select product_id, product_description, product_status, std_shipping_qty
into i_product_id, i_product_description, i_product_status, i_std_shipping_qty
from inventory where product_id=(
select product_id from contract_item where contract_no=&&contract_no and item_no=&&item_no
);
if i_product_status='shipped' then
update contract_item set arrival_date=sysdate+7 contract_no=&&contract_no and item_no=&&item_no;
//这里的elseif 是连着写的
elseif i_product_status='ordered'?then?
update?contract_item?
set?arrival_date=add_months(sysdate,1)?//加一个月
where?item_no=&&itemno?and?contract_no=&&contractno;?
else
update?contract_item?
set?arrival_date=add_months(sysdate,2)?
where?item_no=&&itemno?and?contract_no=&&contractno;?
insert?into?orders?
values(100,i_product_id,i_std_shipping_qty);?
end if;
end if;
commit;
end;