CREATE or REPLACE
PACKAGE BODY employee_pkg as
Procedure print_ename(p_empno number) is
L_ename emp.ename%type;
Begin
Select ename into l_ename from emp where empno=p_empno;
Dbms_output.put_line(l_ename);
Exception
When no_data_found then
Dbms_output.put_line(‘Invalid employee number’);
End print_ename;
Procedure print_sal(p_empno number) is
L_sal emp.sal%type;
Begin
Select sal into l_sal from emp where empno=p_empno;
Dbms_output.put_line(l_sal);
Exception
When NO_DATA_FOUND then
Dbms_output.put_line(‘Invalid employee number’);
End print_sal;
End employee_pkg;
/
执行：
set serveroutput on
exec employee_pkg.print_ename(1234);
exec employee_pkg.print_ename(7782);
exec employee_pkg.print_sal(7782);
过程和函数的重载：
在单独的程序包中定义的共享相同名称的两个或者多个过程和函数。单独的过程和函数必须具有唯一的名称，但是程序包中可以有条件的共享相同的名称。
条件：参数列表在数量、次序或者参数类型上有所区别，比如
procedure foo(p1 varchar2);
procedure foo(p1 number);
procedure foo(p1 varchar2, p2 number);
procedure foo(p1 varchar2, p2 varchar2);
但是：只在参数名称、输入输出模式、或者返回类型上不同，是不够的。比如
procedure foo(p1 varchar2);
procedure foo(p2 varchar2);
procedure foo(p1 in varchar2);
procedure foo(p1 in out varchar2);
例如
desc dbms_output
试验：重载SWAP()
之前的例子：
create or replace
procedure swap(
p1 in out number,
p2 in out number ) as
---
l_temp number;
begin
l_temp := p1;
p1 := p2;
p2 := l_temp;
end swap;
/
该例子只能实现交换数值，我们将其包装，并进行重载，使其也可以交换varchar2 和 date
(1) 建立规范
create or replace package utilities as
procedure swap(p1 in out number, p2 in out number);
procedure swap(p1 in out varchar2,p2 in out varchar2);
procedure swap(p1 in out date,p2 in out date);
end utilities;
/
(2) 建立主体
create or replace package body utilities as
procedure swap(p1 in out number, p2 in out number ) as
l_temp number;
begin
dbms_output.put_line(‘Swapping number’);
l_temp := p1;
p1 := p2;
p2 := l_temp;
end swap;
procedure swap(p1 in out varchar2,p2 in out varchar2) as
l_temp varchar2(32767);
begin
dbms_output.put_line(‘Swapping varchar2’);
l_temp := p1;
p1 := p2;
p2 := l_temp;
end swap;
procedure swap(p1 in out date,p2 in out date) as
l_temp date;
begin
dbms_output.put_line(‘Swapping date’);
l_temp := p1;
p1 := p2;
p2 := l_temp;
end swap;
end utilities;
/
(3) 测试结果：
set serveroutput on
declare
l_num1 number :=1;
l_num2 number :=2;
l_date1 date:= sysdate;
l_date2 date:= sysdate +1;
begin
utilities.swap(l_num1,l_num2);
dbms_output.put_line(‘l_num1=’|| l_num1);
dbms_output.put_line(‘l_num2=’|| l_num2);
utilities.swap(l_date1,l_date2);
dbms_output.put_line(‘l_date1=’|| l_date1);
dbms_output.put_line(‘l_date2=’|| l_date2);
end;
/
程序包中的游标：
在PL/SQL块中，return 子句是游标的可选部分。
在规范中声明游标的时候，必须存在与游标关联的return 子句，表示从游标获取的数据元素类型。
并且游标的select 子句只出现在主体中，不出现在规范中。
Create or replace package cur_pack is
Cursor ord_cur return order_master%rowtype;
Procedure ord_pro (orno varchar2);
End;
/
Create or replace package body cur_pack is
Cursor ord_cur return order_master%rowtype is
Select * from order_master;
Procedure ord_pro (orno varchar2) is
Or_rec order_master%rowtype;
Begin
Open ord_cur;
Loop
Fetch ord_cur into or_rec;
Exit when ord_cur%notfound;
Dbms_output.put_line(‘Return ’|| or_rec.orderno);
End loop;
End ord_pro;
End cur_pack;
/
PRAGMA RESTRICT REFERENCES
P206
限定函数的纯度级别
P197
WNDS: write no data status
RNDS: read no data status
WNPS: write no package status
RNPS: read no package status
Create or replace package pack_me is
Procedure order_proc(orno varchar2);
Function order_fun (ornos varchar2) return varchar2;
Pragma restrict_references(order_fun, WNDS,RNDS);
END;
/
数据字典：
select object_name, object_type
from user_objects
where object_type in (‘PROCEDURE’,’FUNCTION’,’PACKAGE’,’PACKAGE BODY’);
查看用户代码：
desc user_source
select text from user_source where name=’INSERT_INTO_T’ order by line;
desc employee_pkg
包装工具：
将utilities包的主体部分保存在utilities.sql文件中，通过wrap工具加密，只生成oracle认识的格式，保护智力成果
wrap iname=utilities.sql
生成utilities.plb
规范部分：
create or replace package utilities as
procedure swap(p1 in out number, p2 in out number);
procedure swap(p1 in out varchar2,p2 in out varchar2);
procedure swap(p1 in out date,p2 in out date);
end utilities;
/
select text from user_source where name='UTILITIES';
3COME考试频道为您精心整理，希望对您有所帮助，更多信息在http://www.reader8.com/exam/
