Question

我写了以下触发器：

CREATE OR REPLACE TRIGGER check_exprdate_tgr
  BEFORE INSERT OR UPDATE ON coupon
  FOR EACH ROW
BEGIN
  IF(:new.Expiry_date<= SYSDATE)
  THEN
    RAISE_APPLICATION_ERROR(404, 'Coupon Expiry date is not valid. Expiry date must be set to a later date.');
  END IF;
END;

表格如下：

CREATE TABLE customer (
  Id INTEGER 
    CONSTRAINT customer_id_nn NOT NULL,
  Name VARCHAR2(50) 
    CONSTRAINT cutomer_name_nn NOT NULL,
  Surname VARCHAR2(50) 
    CONSTRAINT customer_surname_nn NOT NULL,
  Dob DATE 
    CONSTRAINT customer_date_nn NOT NULL,
  Email VARCHAR2(50),
  Gender VARCHAR2(10)
    CONSTRAINT customer_gender_nn NOT NULL,
  Residence_number Integer 
    CONSTRAINT customer_residenceno_nn NOT NULL,
  Street VARCHAR2(50) 
    CONSTRAINT customer_street_nn NOT NULL,
  Town_id INTEGER,

  CONSTRAINT customer_id_pk PRIMARY KEY(Id),
  CONSTRAINT customer_townId_fk FOREIGN KEY(Town_id) 
      REFERENCES TOWN(Id)
);


CREATE TABLE coupon (
  Id INTEGER,
  Expiry_date DATE
    CONSTRAINT coupon_date_nn NOT NULL,
  Discount_percentage NUMBER(4,2)
    CONSTRAINT coupon_discperc_nn NOT NULL,
  Details VARCHAR2(50),
  Customer_id INTEGER
    CONSTRAINT coupon_customerid_nn NOT NULL,

  CONSTRAINT coupon_id_pk PRIMARY KEY(Id),
  CONSTRAINT coupon_customerid_fk FOREIGN KEY(Customer_id)
    REFERENCES customer(Id)  
);

触发器的目的是检查到期日期输入是否设置在SYSTATE之后的日期。我编译了触发器并且编译正确，所以我真的不知道代码有什么问题。

谢谢：）

Answer 1

RAISE_APPLICATION_ERROR（）中的数字必须在为用户定义的错误（即-20999到-20000）预留的范围内。 It's in the documentation

RAISE_APPLICATION_ERROR(-20404
           , 'Coupon Expiry date is not valid. Expiry date must be set to a later date.');

值得注意的是，每次更新COUPON表上的任何列时，都会评估此行，无论您是否已触及过EXPIRY_DATE：

  IF(:new.Expiry_date<= SYSDATE)

这意味着优惠券到期后您无法更新表格。这可能就是你想要的。否则你应该考虑一个更细微的测试，比如说

   IF ( INSERTING or :new.Expiry_date != :old.Expiry_date )
   AND :new.Expiry_date<= SYSDATE

触发器包含在the PL/SQL Reference。

中

SQL错误：ORA-04098：触发

1 个答案: