Question

我正在尝试获取一个插入后触发器，以便不回滚对innodb表执行的插入操作。 MyISAM似乎没有这个问题。

让我说明一下：

CREATE TABLE `testTable` (
  `id` int(10) AUTO_INCREMENT,
  `data` text,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB; #Engine supports transactions

CREATE TABLE `dummyTable` (
  `id` int(10) AUTO_INCREMENT,
  `data` text,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB;


DELIMITER $$
CREATE TRIGGER triggerTest AFTER INSERT ON `testTable`
FOR EACH ROW
BEGIN
  INSERT INTO dummyTable VALUES(1, 2, 3, 4); #This will throw a column count error
END;$$
DELIMITER ;


INSERT INTO testTable(data) VALUES('This insert will be rolled back');
SELECT COUNT(1) FROM testTable; # 0

如果您将testTable的引擎更改为MyISAM，原始插入将不会回滚，因为（我假设）MyISAM不支持事务。

CREATE TABLE `testTable` (
  `id` int(10) AUTO_INCREMENT,
  `data` text,
  PRIMARY KEY (`id`)
) ENGINE=MyISAM; #Engine does NOT support transactions

CREATE TABLE `dummyTable` (
  `id` int(10) AUTO_INCREMENT,
  `data` text,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB;

DELIMITER $$
CREATE TRIGGER triggerTest AFTER INSERT ON `testTable`
FOR EACH ROW
BEGIN
  INSERT INTO dummyTable VALUES(1, 2, 3, 4); #This will throw a column count error
END;$$
DELIMITER ;

INSERT INTO testTable(data) VALUES('This insert will not be rolled back');
SELECT COUNT(1) FROM testTable; # 1

问题：如果触发器中有错误，InnoDB表的插入触发器是否有保留原始插入的方法？

Answer 1

是的，不同的行为与引擎supports transactions or not：

有关

对于事务表，语句失败应导致回滚语句执行的所有更改。触发器失败会导致语句失败，因此触发器失败也会导致回滚。对于非事务性表，无法进行此类回滚，因此尽管语句失败，但在错误点之前执行的任何更改仍然有效。

declare a CONTINUE handler可以this specific error：

DELIMITER $$
CREATE TRIGGER triggerTest AFTER INSERT ON `testTable`
FOR EACH ROW
BEGIN
  DECLARE CONTINUE HANDLER
      FOR SQLSTATE '21S01' -- "Column count doesn't match value count"
      BEGIN END; -- do nothing (but continue)
  INSERT INTO dummyTable VALUES(1, 2, 3, 4);
END $$
DELIMITER ;

Answer 2

我同意到目前为止所说的一切。显然非事务性存储引擎不会回滚。但是，您可以将触发器更改为BEFORE而不是AFTER触发器，并获得与InnoDB示例中相同的结果，即。未提交的更改如下：

CREATE TABLE `__testTable` (
  `id` int(10) AUTO_INCREMENT,
  `data` text,
  PRIMARY KEY (`id`)
) ENGINE=MyISAM; #Engine does NOT support transactions

CREATE TABLE `dummyTable` (
  `id` int(10) AUTO_INCREMENT,
  `data` text,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB;

DELIMITER $$
CREATE TRIGGER triggerTest BEFORE INSERT ON `__testTable`
FOR EACH ROW
BEGIN
  INSERT INTO dummyTable VALUES(1, 2, 3, 4); #This will throw a column count error
END;$$
DELIMITER ;

INSERT INTO __testTable(data) VALUES('This insert will not occur!');
SELECT COUNT(1) FROM __testTable; # 1

插入触发器后的MySQL - MyISAM与InnoDB

2 个答案: