Question

我已经创建了一个从三个表中删除数据的过程，这三个表都与外键链接但是没有运行。这是程序。

PROCEDURE remove_customer (customer_id VARCHAR2) IS
BEGIN
DELETE FROM order_line
WHERE  order_line.order_id = placed_order.order_id;
DELETE FROM placed_order
WHERE placed_order.customer_id = customer.customer_id;
DELETE FROM customer
WHERE customer.customer_id = remove_customer.customer_id;
total_customers := total_customers - 1;
END;

这是三个表的结构。任何人都知道我为什么会出错？

customer(
    Customer_ID INTEGER NOT NULL,
    Country VARCHAR(15),
    First_Name  VARCHAR(30),
    Last_Name   VARCHAR(30),
    CONSTRAINT  pk_customer PRIMARY KEY (Customer_ID)
);


    placed_order(
    order_id    INTEGER NOT NULL,
    order_date  VARCHAR(15),
    fk1_Customer_ID INTEGER NOT NULL,
    fk2_Employee_ID INTEGER NOT NULL,
    fk3_order_type_id   INTEGER NOT NULL,
    CONSTRAINT  pk_placed_order PRIMARY KEY (order_id)
);


    order_line(
    order_line_id   INTEGER NOT NULL,
    fk1_order_id    INTEGER NOT NULL,
    fk2_product_id  INTEGER NOT NUL,
    CONSTRAINT  pk_order_line PRIMARY KEY (order_line_id)
);

以下是它抛出的两个错误。

ORA-00904：“PLACED_ORDER”。“ORDER_ID”：无效的identifierCompilation失败，第30行

ORA-00904：“CUSTOMER”。“CUSTOMER_ID”：无效的identifierCompilation失败，第32行

Answer 1

您不能仅在DELETE语句中引用其他表中的列。每个语句都需要从参数值customer_id开始。这应该做你想要的：

PROCEDURE remove_customer (customer_id VARCHAR2) IS
BEGIN

  DELETE FROM order_line
  WHERE  order_line.order_id in
  ( SELECT order_id FROM placed_order
    WHERE placed_order.customer_id = remove_customer.customer_id
  );

  DELETE FROM placed_order
  WHERE placed_order.customer_id = remove_customer.customer_id;

  DELETE FROM customer
  WHERE customer.customer_id = remove_customer.customer_id;

  total_customers := total_customers - 1;

END;

删除程序不会运行并出错？

1 个答案: