Oracle 异常处理

RAISE_APPLICATION_ERROR

/*
===========================================================
|         使用RAISE_APPLICATION_ERROR存储过程。
============================================================
*/
--演示该存储过程
BEGIN
      RAISE_APPLICATION_ERROR(-20000, 'Account past due.');-- explicitly raise exception
END;

--创建子程序
CREATE OR REPLACE PROCEDURE account_status (
   due_date DATE,
   today DATE
) 
IS
BEGIN
   IF due_date < today THEN 
      RAISE_APPLICATION_ERROR(-20000, 'Account past due.');-- explicitly raise exception
   END IF;
END;
/

--调用子程序
DECLARE
   past_due EXCEPTION; -- declare exception
   PRAGMA EXCEPTION_INIT (past_due, -20000); 
BEGIN
    account_status (to_date('2010-7-9','yyyy-mm-dd'), to_date('2010-7-10','yyyy-mm-dd')); -- invoke procedure
EXCEPTION
   WHEN past_due THEN -- handle exception
       DBMS_OUTPUT.PUT_LINE(TO_CHAR(SQLERRM(-20000)));
END;

/*
===========================================================
|         使用用户自定义实现。
============================================================
*/


CREATE OR REPLACE PROCEDURE account_status (
   due_date DATE,
   today DATE
) 
IS
 past_due EXCEPTION; -- declare exception
BEGIN
   IF due_date < today THEN 
      RAISE past_due; -- explicitly raise exception
   END IF;
EXCEPTION
   WHEN past_due THEN -- handle exception
      DBMS_OUTPUT.PUT_LINE ('Account past due.');
     -- INSERT INTO t VALUES(due_date);
END;
/
--调用子程序

BEGIN
   account_status ('2010-7-9', '2010-7-10'); -- invoke procedure
END;

用户自定义异常

/*
===========================================================
|         查询编号为7788的雇员的福利补助（comm列）。
============================================================
*/
DECLARE
 	v_comm employee.comm%TYPE;
	e_comm_is_null EXCEPTION; --定义异常类型变量
BEGIN
	SELECT comm INTO v_comm FROM employee WHERE empno=7788;
	IF v_comm IS NULL THEN
	   RAISE e_comm_is_null;
	END IF;
EXCEPTION
    WHEN NO_DATA_FOUND THEN
       dbms_output.put_line('雇员不存在！错误为:'||SQLCODE||SQLERRM);
    WHEN e_comm_is_null THEN
	     dbms_output.put_line('该雇员无补助');
    WHEN others THEN
	     dbms_output.put_line('出现其他异常');
END;

非预定义异常

/*
===========================================================
|         非预定义异常
============================================================
*/

--需求：修改编号为7788的雇员所属的部门编号为99。
--前提是要在employee和dept表建立主外键约束
ALTER TABLE employee 
   ADD  CONSTRAINT pk_empno PRIMARY KEY(empno);
ALTER TABLE dept 
   ADD  CONSTRAINT pk_deptno PRIMARY KEY(deptno);
ALTER TABLE employee 
   ADD  CONSTRAINT fk_deptno FOREIGN KEY(deptno) REFERENCES dept(deptno);

DECLARE
   e_integrity EXCEPTION;
   PRAGMA EXCEPTION_INIT(e_integrity,-2291);  --  -2291为Oracle定义的错误号，违背了主外键约束
BEGIN
 update employee set deptno=99 where empno=7788;
EXCEPTION
   WHEN e_integrity THEN
      dbms_output.put_line('该部门不存在');
END;

SELECT * FROM employee;

预定义异常

/*
===========================================================
|         预定义异常
============================================================
*/
--未进行异常处理
DECLARE   
   v_ename employee.ename%TYPE;
BEGIN
   SELECT ename INTO v_ename 
   FROM employee     
   WHERE empno=1234;
   dbms_output.put_line('雇员名:'||v_ename);
END;

--进行异常处理
DECLARE
   v_ename employee.ename%TYPE;
BEGIN
   SELECT ename INTO v_ename 
   FROM employee 
   WHERE empno=1234;
   dbms_output.put_line('雇员名:'||v_ename);
EXCEPTION
   WHEN NO_DATA_FOUND THEN
      dbms_output.put_line('雇员号不正确');   
   WHEN TOO_MANY_ROWS THEN
      dbms_output.put_line('查询只能返回单行');
   WHEN OTHERS THEN
      dbms_output.put_line('错误号：'||SQLCODE||'错误描述：'||SQLERRM);
END;