函数

Question

我正在尝试在我的oracle PL / SQL程序中生成DIVIDE_BY_ZERO异常。我使用函数但是当我运行我的程序时，我收到错误，如下所示。谁能告诉我程序中有什么问题？

代码：

 CREATE OR REPLACE 
PACKAGE CALCULATOR AS 

  FUNCTION AddNumber(addend IN Number, Addend2 IN Number) RETURN NUMBER;
  FUNCTION DivNumber(divend IN Number, divend2 IN Number) RETURN NUMBER;

END CALCULATOR;
/

CREATE OR REPLACE
PACKAGE BODY CALCULATOR AS

  FUNCTION AddNumber(addend IN Number, Addend2 IN Number) RETURN NUMBER AS
  BEGIN
     return addend + addend2; 

  END AddNumber;

  FUNCTION DivNumber(divend IN Number, divend2 IN Number) RETURN NUMBER AS
  BEGIN
         return divend / divend2;
         EXCEPTION 
         WHEN ZERO_DIVIDE THEN
         NULL;    
  END DivNumber;

END CALCULATOR;
/

select calculator.AddNumber(3,4) from dual;
select calculator.DivNumber(12,0) from dual;

输出：

Answer 1

你可以处理像这样的例外

FUNCTION DivNumber(divend IN Number, divend2 IN Number) RETURN NUMBER AS
 e_ZERO_DIVIDE EXCEPTION;
 BEGIN
-- the condition
  IF divend2 = 0 THEN 
    Raise e_ZERO_DIVIDE; 
   END IF;
 return divend / divend2;
--Exception handling  
EXCEPTION 
WHEN e_ZERO_DIVIDE THEN
   dbms_output.put_line('Division by 0 or null');
   RETURN 1;
 WHEN OTHERS THEN
  dbms_output.put_line('ERROR: '||sqlerrm);
  RETURN 1;
 END DivNumber;

Answer 2

IMO你永远不应该写出引发可避免异常的代码。有时你可能无法避免提出异常但在这种情况下你可以。我建议您按如下方式重写您的功能：

FUNCTION DivNumber(numerator IN Number, denominator IN Number) RETURN NUMBER AS
BEGIN
  IF NVL(denominator, 0) <> 0 THEN
     return numerator / denominator;
  ELSE
    RETURN NULL;
  END IF;
END DivNumber;

祝你好运。