Oracle PL/SQL程序设计 实验六

实验内容

以bs用户登录BOOKSALES数据库，利用PL/SQL程序编写下列功能模块。
SQL>CONN bs/bs@booksales

（1）创建一个函数，以客户号为参数，返回该客户订购图书的价格总额。

create or replace function sumprice(
    id customers.customer_id%type)
    return books.cost%type
    as
    sumprice books.cost%type;
    begin
    select sum(quantity*cost) into sumprice from customers,books,orders,orderitem
    where customers.customer_id = orders.customer_id and orders.order_id = orderitem.order_id and orderitem.isbn = books.isbn and customers.customer_id = id;
    return sumprice;
   exception
     when no_data_found then
       dbms_output.put_line('the id is invaild!');
   end sumprice;
 
   /

（6）创建一个存储过程，输出不同类型图书的数量、平均价格。

 create or replace procedure books_msg
    as
    books_count orderitem.quantity%type;
    begin
      for emp in (
        select title,ISBN,cost from books
    )
    loop
    select sum(quantity) into books_count from orderitem where ISBN=emp.ISBN;
       dbms_output.put_line(emp.title||'  单价：'||emp.cost||'  数量：'||books_count);
       end loop;
   end books_msg;
   /

（18）创建一个触发器，禁止客户在非工作时间（早上8：00之前，晚上17：00之后）下订单。

CREATE OR REPLACE TRIGGER trg_orderitem
    BEFORE INSERT OR UPDATE OR DELETE ON orderitem
    BEGIN
      IF TO_CHAR(SYSDATE,'HH24:MI') NOT BETWEEN '08:00' AND '17:00'
        OR TO_CHAR(SYSDATE,'DY','NLS_DATE_LANGUAGE=AMERICAN') IN ('SAT','SUN')
      THEN
      RAISE_APPLICATION_ERROR(-20005,'只能在正常的时间内进行改变。');
        END IF;
    END trg_orderitem;
   /

检查

调用函数看结果；

declare
    sprice books.cost%type;
    begin
    sprice:=sumprice(1);
    dbms_output.put_line('价格'||sprice);
    exception
    when no_data_found then
    dbms_output.put_line('not found');
    end;
   /

执行存储过程看结果；

触发触发器看结果

insert into orderitem values('1000','1','978-7-121-18619-8','5');