未引发触发 if-else 语句错误

Question

我已经创建了一个程序和一个触发器，我打算支付票价，输入的票价金额必须大于或等于付款中的确切金额 Table

从table开始，我的意思是，用户需要输入足够的金额才能继续存储过程，如果输入的金额低于该金额，则会引发触发器错误！

程序

CREATE OR REPLACE PROCEDURE PRC_PAY_TRIP
    (CUST_ID IN NUMBER,PAYMENT_ID IN NUMBER,PAYMENT_TYPE IN VARCHAR2,AMT_PAY IN NUMBER)
AS
    v_paymentstatus VARCHAR2(15) := 'Paid';
    v_temppaymentid NUMBER(4) := PAYMENT_ID;
    v_truenumber NUMBER(10);
    
    no_null_on_custID EXCEPTION;
    no_null_on_payID EXCEPTION;
    invalid_paymentid EXCEPTION;
    invalid_paymenttype EXCEPTION;
    invalid_paymentamt EXCEPTION;
    
BEGIN
    v_truenumber := v_temppaymentid-1000;    
    
    IF CUST_ID < 0
    THEN
        RAISE no_null_on_custID;
    END IF;
    
    IF PAYMENT_ID < 0
    THEN
        RAISE no_null_on_payID;
    END IF;
    
    IF CUST_ID ^= v_truenumber THEN
        RAISE invalid_paymentid;
    END IF;
    
    IF PAYMENT_TYPE ^= 'Cash' AND PAYMENT_TYPE ^= 'E-Wallet' THEN
        RAISE invalid_paymenttype;
    END IF;
    
    IF AMT_PAY < 0 THEN
        RAISE invalid_paymentamt;
    END IF;

    UPDATE Payment
    SET paymenttype = PAYMENT_TYPE,paymentdate = TO_CHAR(sysdate,'DD/MON/YYYY'), paymentstatus = v_paymentstatus
    where paymentid = PAYMENT_ID;
   
EXCEPTION    
    WHEN no_null_on_custID then
        DBMS_OUTPUT.PUT_LINE('Invalid Customer ID');
    
    WHEN no_null_on_payID then
        DBMS_OUTPUT.PUT_LINE('Invalid Payment ID');
    
    WHEN invalid_paymenttype then
        DBMS_OUTPUT.PUT_LINE('You can either choose Cash or E-Wallet only!');
    
    WHEN invalid_paymentid then
        DBMS_OUTPUT.PUT_LINE('Payment id is not yours, just add 1000 from your Customer ID and that will be your Payment ID');
    
    WHEN invalid_paymentamt then
        DBMS_OUTPUT.PUT_LINE('Amount pay cannot be negative value!');
END;
/

触发

CREATE OR REPLACE trigger trg_payment_validation
before update on payment
for each row
BEGIN 
    if :NEW.paymentamount < :OLD.paymentamount then >>> this error could not be raised even after
                                                        the amount entered is lower than the
                                                        actual amount
        RAISE_APPLICATION_ERROR(
          -20950,
          'Insufficient amount entered, pls pay the exact amount'
        );
    elsif :OLD.paymentstatus = 'Paid' then
        RAISE_APPLICATION_ERROR(
          -20950,
          'You cannot pay the fares as you already paid before this, have a nice day'
        );
    end if;
END;
/

Answer 1

当您手动更新 table 时，触发器会按预期工作。

当从过程中调用时，触发器不会报告无效金额，并显示已支付的全部金额，即使它不是 - 支付金额未更改，但其他列已更改。

那是因为你程序的更新语句是：

UPDATE Payment
SET paymenttype = PAYMENT_TYPE,
  paymentdate = TO_CHAR(sysdate,'DD/MON/YYYY'),
  paymentstatus = v_paymentstatus
where paymentid = PAYMENT_ID;

您没有告诉它更新金额，因此触发器没有修改后的 :new 值 - 新旧值相同。您需要在更新中包括该列：

UPDATE Payment
SET paymenttype = PAYMENT_TYPE,
  paymentdate = TO_CHAR(sysdate,'DD/MON/YYYY'),
  paymentamount = amt_pay,
  paymentstatus = v_paymentstatus
where paymentid = PAYMENT_ID;

db<>fiddle

TO_CHAR(sysdate,'DD/MON/YYYY') 看起来很奇怪 - table 列应该是日期而不是字符串，因此您不应该将该值转换为字符串；如果该列是日期，那么您将依靠客户端的 NLS 设置将其转换回来。如果您想忽略当前时间，则可以改为 TRUNC(sysdate)。

您也不应该依赖过程主体中的 dbms_output - 您无法控制调用它的人是否启用了输出，因此他们可能永远看不到问题。当您在触发器中引发异常时，您可以在其他错误的过程中执行相同的操作。

未引发触发 if-else 语句错误

Trigger if-else statement error not being raised

sql

oracle

triggers

plsql

stored-procedures

程序

触发