Question

我想要一种在语句或视图为真时更新表的方法。触发器和存储过程的问题在于它们依赖于用户操作，即编辑，删除或更新。我需要的是一个表，只要给定的语句根据系统日期变为真实，就会被更新。实现如下：

查看

    CREATE VIEW `vw_dueusers` AS
    select UserID,Penalty from indextbl
        where duedate>now() and balance>0;

程序

    DELIMITER $$
    CREATE PROCEDURE sp_PenaltyInsert(
      in vUserID int,
      in vPenalty text
    )
    -- Wonder how to get the variables from the View above for my INs
    begin
    INSERT INTO `penaltytbl`
    -- The idea is to keep updating this table whenever when user doesnt pay on agreed date
    (
    UserID,
    Penalty
    )
    select UserID,Penalty from indextbl
        where  duedate>now() and balance>0;
        -- or
    --select * from vw_dueusers;
    -- How to avoid duplicate entries?
    end

TRIGGER ????想知道我是否创建得很好

    DELIMITER $$
    CREATE TRIGGER Tr_PenaltyInsert BEFORE INSERT ON indextbl
    -- the idea is automation and not relying on the Insert Action. Once the view above becomes true
    -- the balance doesnt become due, due to an insert but when user doesnt pay on agreed date
      FOR EACH ROW
      BEGIN
      Declare vUserID int;
      Declare vPenalty int;
        set new.vUserID =(select UserID from indextbl where duedate>now() and balance>0);
        set new.vPenalty =(select Penalty from indextbl where  duedate>now() and balance>0);
            INSERT INTO `penaltytbl`
            (
            UserID,
            Penalty
            )
            values
            (
            vUserID,
            vPenalty
            );
        /*values
        (
        New.vUserID,
        New.vPenalty
        );*/
    -- How to avoid duplicate entries?
      END;

事件？

语句/视图为真时调用（触发，函数，存储过程或事件）的方法

0 个答案: