Mysql 防止在某个日期后插入

Question

是否可以在某个日期和时间后阻止在 mysql 表中插入？

例如我有 2 个表:

TABLE exams 
(
...
examID int primary key auto_increment,
examDate DATE,
examTime TIME, 
...
)


TABLE inscripts
(
...
examID int not null references exams(examID),
insDate DATE,
insTime TIME,
...
)

我想防止在考试时插入新题词。

如果当前日期和当前时间等于或大于匹配表中的日期和时间，是否有一些功能可以防止这种情况或轻松检查？

Answer 1

你可以 create a trigger在继续之前验证插入。伪代码，但类似于:

DELIMITER |
CREATE TRIGGER `Stop_Insert_During_Exam`
BEFORE UPDATE ON `inscripts`
FOR EACH ROW
BEGIN
  DECLARE msg VARCHAR(255);
  -- Check
  -- Test if an exam is going on. If so:
  SET msg = "You cannot add an inscription while an exam is going on.';
  SIGNAL SQLSTATE '45000' SET MESSAGE_TEXT = msg;
  -- /Check
END;
|