实验 6 PL/SQL 程序设计1 实验目的(1) 掌握 PL/SQL程序开发方法。(2) 掌握存储过程、函数、触发器、包的创建于调用。2 实验要求(1) 根据图书销售系统业务要求创建特定的存储过程、函数、触发器。(2) 根据图书销售系统业务要求将图书销售系统相关的函数、存储过程封装到包里。3 实验步骤以 bs 用户登录BOOKSALES数据库,利用PL/SQL 程序编写下列功能模块。(1) 创建一个存储过程,输出不同类型图书的数量、平均价格。SQL> create or replace procedure proc_category_static 2 as 3 --定义游标,获取当前有哪些图书种类 4 cursor c_all_category is select distinct category from books; 5 --图书的平均价格 6 v_avg_cost number; 7 begin 8 --保存图书种类 9 for v_each_category in c_all_category LOOP 10 select avg(retail) into v_avg_cost from books where category=v_each_category.category group by category; 11 dbms_output.put_line('种类为:'||v_each_category.category||',平均价格为: '|| v_avg_cost); 12 END LOOP; 13 end proc_category_static; 14 / (2) 创建一个存储过程,以客户号为参数,输出该客户订购的所有图书的名称与数量。create or replace procedure proc_get_orderinfo( 2 p_customer_id customers.customer_id%type) 3 as 4 --声明游标存储客户的订单号 5 cursor c_orderid is select order_id from orders where customer_id=p_customer_id; 6 v_orderid orders.order_id%type; 7 --声明游标存储订单信息 8 cursor c_orderitem is select ISBN, sum(quantity) totalnum from orderitem where order_id=v_orderid group by ISBN; 9 --保存图书的书名 10 v_title books.title%type; 11 12 begin 13 open c_orderid; 14 LOOP 15 fetch c_orderid into v_orderid; 16 exit when c_orderid%NOTFOUND; 17 for v_orderitem in c_orderitem LOOP 18 select title into v_title from books where ISBN=v_orderitem.ISBN; 19 DBMS_OUTPUT.PUT_LINE(p_customer_id||'订购 '||v_title||'的数量是'||v_orderitem.totalnum); 20 end LOOP; 21 end LOOP; 22 close c_orderid; 23 end proc_get_orderinfo; 24 / exec proc_get_orderinfoo(1001)...