这是我的代码：
create table orderline
(
Order_No number(4) constraint orderno_fk references order_detail(Order_No),
Product_Code varchar2(6) constraint productcode2_fk references product(Product_Code),
Product_Size char(1) constraint productsize_fk references product_stock(Product_Size),
Product_Quantity number(4) not null
constraint orderline_comp primary key (Order_No,Product_Code, Product_Size)
);
我得到的错误（以“订单”前左括号下方的星）：
ERROR at line 7:
ORA-00907: missing right parenthesis
