oracle高级用法之自定义函数

注意：终端使用dbms_output输出执行结果，首先PL/SQL开启服务器输出

set serveroutput on;

/* 用户自定义函数 */

-- 查看函数、触发器
select * from user_source;

-- 删除函数
drop function fun_getCurDate;

-- 创建函数

1. 建立无参数的函数:获取当前日期
create or replace function fun_getCurDate
return varchar2
is
begin
  return to_char(sysdate,'yyyy-mm-dd');
end;

select fun_getCurDate() from dual;

BEGIN
  dbms_output.put_line(fun_getCurDate);
END;

2.建立带有输入参数的函数:根据姓名获取工资
CREATE OR REPLACE FUNCTION fun_getSal(name VARCHAR2)
RETURN NUMBER
AS v_sal emp.sal%TYPE;
BEGIN
  SELECT sal INTO v_sal FROM emp WHERE UPPER(ename)=UPPER(name);
  RETURN v_sal;
END;

select fun_getSal(name=>'libing') salary from dual;

3. 建立带有输出参数的函数：
CREATE OR REPLACE FUNCTION fun_getInfo(eno NUMBER,title OUT VARCHAR2) 
RETURN VARCHAR2  
AS NAME emp.ename%TYPE;  
BEGIN  
   SELECT ename,job INTO name,title FROM emp WHERE empno=eno;  
   RETURN name;  
END; 

4. 建立带有输入输出参数的函数：
CREATE OR REPLACE FUNCTION fun_getUpdInfo(eno NUMBER,sal_chg IN OUT NUMBER) RETURN VARCHAR2  
AS  
name emp.ename%TYPE;  
BEGIN  
     UPDATE emp SET sal=sal+sal_chg WHERE empno=eno  
     RETURNING ename,sal INTO name,sal_chg;  
     RETURN name;  
END; 

DROP FUNCTION get_upd_info;

5.建立结果缓存函数
CREATE OR REPLACE FUNCTION fun_getName(eno VARCHAR2)
RETURN NUMBER result_cache relies_on(emp)
AS v_name emp.ename%TYPE;
BEGIN
  SELECT ename INTO v_name FROM emp WHERE empno = eno;
  RETURN v_name;  
END

6.使用异常处理
CREATE OR REPLACE FUNCTION get_sal(NAME VARCHAR2)
RETURN NUMBER
AS
v_sal emp.sal%TYPE;
BEGIN
  SELECT sal INTO v_sal FROM emp WHERE UPPER(ename)=UPPER(NAME);
  RETURN v_sal;
  EXCEPTION
    WHEN no_data_found THEN
      raise_application_error(-20005,'该雇员不存在');
END;

SELECT get_sal('lily')salary FROM dual;

7.使用记录类型作为返回类型
CREATE OR REPLACE FUNCTION get_info(eno NUMBER)
RETURN emp%ROWTYPE
IS
emp_record emp%ROWTYPE;
BEGIN
  SELECT * INTO emp_record FROM emp WHERE empno=eno;
  RETURN emp_record;
  EXCEPTION
    WHEN no_data_found THEN
      raise_application_error(-20006,'该雇员不存在');
END;

8.使用集合类型作为返回类型
CREATE OR REPLACE TYPE ename_table_type IS TABLE OF VARCHAR2(10);

CREATE OR REPLACE FUNCTION get_name(dno NUMBER)
RETURN ename_table_type
IS ename_table ename_table_type;
BEGIN
  SELECT ename BULK COLLECT INTO ename_table FROM emp WHERE deptno = dno;
  RETURN ename_table;
  EXCEPTION
    WHEN no_data_found THEN
      raise_application_error(-20006,'该部门不存在');

END;