Oracle 程序不能正常工作？

Question

SPOOL /Users/gongjiaxi/Desktop/solution2
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SET SERVEROUTPUT ON
create PROCEDURE INSERT_ORDER_DETAIL(order_id ORDER_DETAIL.ORDER_ID%TYPE,
                                     product_name ORDER_DETAIL.PRODUCT_NAME%TYPE,
                                     unit_price ORDER_DETAIL.UNIT_PRICE%TYPE,
                                     quantity ORDER_DETAIL.QUANTITY%TYPE,
                                     discount ORDER_DETAIL.DISCOUNT%TYPE)
    IS
    discontinued PRODUCT.DISCONTINUED%TYPE;
BEGIN
    IF discontinued = 'N' THEN
        INSERT INTO ORDER_DETAIL(ORDER_ID, PRODUCT_NAME, UNIT_PRICE, QUANTITY, DISCOUNT)
        VALUES (order_id, product_name, unit_price, quantity, discount);
    end if;
    IF discontinued = 'Y' THEN
        DBMS_OUTPUT.PUT_LINE('The product is not availiable');
    end if;
end;
/
EXECUTE INSERT_ORDER_DETAIL(1000,'Chai',18.00,1002,0.9);
EXECUTE INSERT_ORDER_DETAIL(1000,'Alice Mutton', 39.00,1000,0.8);

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但结果是

Procedure INSERT_ORDER_DETAIL compiled

SQL> EXECUTE INSERT_ORDER_DETAIL(1000,'Chai',18.00,1002,0.9);

PL/SQL procedure successfully completed.

SQL> EXECUTE INSERT_ORDER_DETAIL(1000,'Alice Mutton', 39.00,1000,0.8);

PL/SQL procedure successfully completed."

我执行的两条数据中的一条应该将一条数据插入到表中，另一条应该调用 DBMS_OUTPUT。但是没有一个成功。

Answer 1

您需要从product 表中获取产品是否已停产，然后在IF 条件下使用它。

...
...
IS
    discontinued PRODUCT.DISCONTINUED%TYPE;
BEGIN
Select discontinued -- this is column name from your product table
Into discontinued -- this is a variable declared in your procedure
From product 
where name = product_name;
-- name is column name of the product table
-- product_name is input parameter of the procedure

IF discontinued = 'N' THEN
...
...

Suggestion: 为变量/参数使用与表的列名不同的名称。

Answer 2

你声明了变量discontinued PRODUCT.DISCONTINUED%TYPE; 没有用值初始化它，所以它的值是NULL。
然后在过程中检查 IF 语句中此变量的值
但 NULL 既不是 Y 也不是 N，所以程序什么也不做。