Question

我试图制作一个触发器，阻止您将新的Bill Item插入＆＃34; Bill_Item＆＃34;如果该法案已经支付，则为表格。比尔表中有一个Paid_YN和一个Posted_YN列。因此，根据您要添加的帐单，如果已付款或过帐，则会拒绝该帐单。我的更新和删除部分在此代码中工作，但不是＆＃34;插入＆＃34;部分。请帮忙！我抱歉没有缩进，无法正确复制代码。请让我知道我哪里错了！这是我的逻辑吗？我已经尝试谷歌搜索并在这里搜索错误消息，但仍然无法弄明白！

TABLES ::

CREATE TABLE Bill (
Bill_Number NUMBER (6,0)
CONSTRAINT Bill_pk PRIMARY KEY
CONSTRAINT Bill_Number_NN NOT NULL,
Bill_Date DATE DEFAULT SYSDATE
CONSTRAINT Bill_Date_NN NOT NULL,
Waiter_Number NUMBER (5,0)
CONSTRAINT Bill_Waiter_Number_FK REFERENCES Waiter (Waiter_Number)
CONSTRAINT Bill_Waiter_Number_NN NOT NULL,
Table_Number NUMBER (2,0)
CONSTRAINT Bill_Table_Number_NN NOT NULL,
Customer_Count NUMBER (2,0) DEFAULT 1
CONSTRAINT Bill_Customer_Count_CK CHECK (Customer_Count > 0)
CONSTRAINT Bill_Customer_Count_NL NULL,
Paid_YN CHAR (1) DEFAULT 'N'
CONSTRAINT Bill_Paid_YN_CK CHECK ((Paid_YN = 'Y') OR (Paid_YN = 'N'))
CONSTRAINT Bill_Paid_YN_NN NOT NULL,
Posted_YN CHAR (1) DEFAULT 'N'
CONSTRAINT Bill_Posted_YN_CK CHECK ((Posted_YN = 'Y') OR (Posted_YN = 'N'))
CONSTRAINT Bill_Posted_YN_NN NOT NULL,
Bill_GST NUMBER (6,2) DEFAULT 0
CONSTRAINT Bill_GST_CK CHECK (Bill_GST >= 0)
CONSTRAINT Bill_GST_NN NOT NULL,
Bill_Total NUMBER (8,2) DEFAULT 0
CONSTRAINT Bill_Total_CK CHECK (Bill_Total >= 0)
CONSTRAINT Bill_Total_NN NOT NULL
);

CREATE TABLE Bill_Item (
Bill_Number NUMBER (6,0)
CONSTRAINT BItem_Bill_Number_FK REFERENCES Bill (Bill_Number)
CONSTRAINT BItem_Bill_Number_NN NOT NULL,
Menu_Item_Number NUMBER (5,0)
CONSTRAINT BItem_Menu_Item_Number_FK REFERENCES Menu_Item (Menu_Item_Number)
CONSTRAINT BItem_Menu_Item_Number_NN NOT NULL,
Discount NUMBER (5,2) DEFAULT 0
CONSTRAINT BItem_Discount_CK CHECK ((Discount >= 0 ) AND (Discount <= 100))
CONSTRAINT BItem_Discount_NL NULL,
Quantity_Sold NUMBER (3,0) DEFAULT 1
CONSTRAINT BItem_Quantity_Sold_CK CHECK (Quantity_Sold > 0)
CONSTRAINT BItem_Quantity_Sold_NN NOT NULL,
Selling_Price NUMBER (6,2) DEFAULT 0
CONSTRAINT BItem_Selling_Price_CK CHECK (Selling_Price >= 0)
CONSTRAINT BItem_Selling_Price_NN NOT NULL,
CONSTRAINT Bill_Item_PK PRIMARY KEY (Bill_Number, Menu_Item_Number)
);

触发::

CREATE OR REPLACE TRIGGER TR_Q5 
BEFORE 
  UPDATE OR
  INSERT OR
  DELETE ON
  BILL_ITEM
  FOR EACH ROW

DECLARE
 v_Paid_YN CHAR(1);
 v_Posted_YN CHAR(1);

BEGIN
  IF UPDATING THEN
    SELECT Paid_YN, Posted_YN
    INTO v_paid_YN, v_Posted_Yn
    FROM Bill
    WHERE Bill_Number = :OLD.Bill_Number;
    IF v_Paid_YN = 'Y' AND
      v_Posted_YN = 'N' THEN
      RAISE_APPLICATION_ERROR(-20001, 'Cannot update the bill once its been paid!');
    END IF;
    IF v_Posted_YN = 'Y' AND
      v_Paid_YN = 'N' THEN
      RAISE_APPLICATION_ERROR(-20002, 'Cannot update the bill once its been posted!');
    END IF;
    IF v_Paid_YN = 'Y' AND
      v_Posted_YN = 'Y' THEN
      RAISE_APPLICATION_ERROR(-20003, 'Cannot update the bill once its been paid and posted!');
    END IF;
  ELSIF INSERTING THEN
    SELECT Paid_YN, Posted_YN
    INTO v_paid_YN, v_Posted_Yn
    FROM Bill
    WHERE Bill_Number = :OLD.Bill_Number;
    IF v_Paid_YN = 'Y' AND
      v_Posted_YN = 'N' THEN
      RAISE_APPLICATION_ERROR(-20004, 'Cannot add to the bill once its been paid!');
    END IF;
    IF v_Posted_YN = 'Y' AND
      v_Paid_YN = 'N' THEN
      RAISE_APPLICATION_ERROR(-20005, 'Cannot add to the bill once its been posted!');
    END IF;
    IF v_Paid_YN = 'Y' AND
      v_Posted_YN = 'Y' THEN
      RAISE_APPLICATION_ERROR(-20006, 'Cannot add to the bill once its been paid and posted!');
    END IF;
  ELSIF DELETING THEN
    SELECT Paid_YN, Posted_YN
    INTO v_paid_YN, v_Posted_Yn
    FROM Bill
    WHERE Bill_Number = :OLD.Bill_Number;
    IF v_Paid_YN = 'Y' AND
      v_Posted_YN = 'N' THEN
      RAISE_APPLICATION_ERROR(-20007, 'Cannot delete from the bill once its been paid!');
    END IF;
    IF v_Posted_YN = 'Y' AND
      v_Paid_YN = 'N' THEN
      RAISE_APPLICATION_ERROR(-20008, 'Cannot delete from the bill once its been posted!');
    END IF;
    IF v_Paid_YN = 'Y' AND
      v_Posted_YN = 'Y' THEN
      RAISE_APPLICATION_ERROR(-20009, 'Cannot delete from the bill once its been paid and posted!');
    END IF;
END IF;
END TR_Q5;
/
SHOW ERRORS;

AND此插入返回：

Insert Into Bill_Item
    (Bill_Number, Menu_Item_Number, Discount, Quantity_Sold, Selling_Price)
Values
  (4945, 2, 0, 1, 1.03);


Error starting at line : 234 in command -
Insert Into Bill_Item
    (Bill_Number, Menu_Item_Number, Discount, Quantity_Sold, Selling_Price)
Values
   (4945, 2, 0, 1, 1.03)
Error report -
SQL Error: ORA-01403: no data found
ORA-06512: at "ORCL1_05.TR_Q5", line 24
ORA-04088: error during execution of trigger 'ORCL1_05.TR_Q5'
01403. 00000 -  "no data found"
*Cause:    No data was found from the objects.
*Action:   There was no data from the objects which may be due to end of 
fetch.

Answer 1

这是你的大事：

  ELSIF INSERTING THEN
    SELECT Paid_YN, Posted_YN
    INTO v_paid_YN, v_Posted_Yn
    FROM Bill
    WHERE Bill_Number = :OLD.Bill_Number;

在INSERT期间，:old命名空间为空。这是完全符合逻辑的：我们正在插入记录，旧记录还有什么其他内容？

所以解决方案很简单

  ELSIF INSERTING THEN
    SELECT Paid_YN, Posted_YN
    INTO v_paid_YN, v_Posted_Yn
    FROM Bill
    WHERE Bill_Number = :NEW.Bill_Number;

在UPDATING和DELETING时，

:old有效，这就是这些分支工作的原因。（通常在UPDATING时测试当前 - :new - 值，除非检查值是否已更改。）

Oracle Trigger BEFORE INSERT没有找到数据

1 个答案: