MySQL 回滚重复键

Question

我期待在出现错误(如重复键或其他)时使用事务和回滚。

当我禁用自动提交并且出现错误时，事务已经提交，即使它们不应该提交也是如此。

这是我的代码的一部分:

CREATE TABLE `Users` (
  `user_id` int(11) DEFAULT NULL,
  PRIMARY KEY (`user_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

CREATE TABLE `Miscs` (
  `misc_id` int(11) DEFAULT NULL,
  PRIMARY KEY (`misc_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

SET @@AUTOCOMMIT = 0;

BEGIN;
    INSERT INTO Miscs ( misc_id ) VALUES('1');
    INSERT INTO Users ( user_id ) VALUES('1');
    INSERT INTO Miscs ( misc_id ) VALUES('2');
COMMIT;

BEGIN;
    INSERT INTO Miscs ( misc_id ) VALUES('3');
    INSERT INTO Users ( user_id ) VALUES('2');
    INSERT INTO Miscs ( misc_id ) VALUES('4');
COMMIT;

BEGIN;
    INSERT INTO Miscs ( misc_id ) VALUES('5');
    INSERT INTO Users ( user_id ) VALUES('1');
    -- should stop, rollback the transaction and skip to the next/last
    INSERT INTO Miscs ( misc_id ) VALUES('6');
COMMIT;

-- last transaction
BEGIN;
    INSERT INTO Miscs ( misc_id ) VALUES('7');
    INSERT INTO Users ( user_id ) VALUES('4');
    INSERT INTO Miscs ( misc_id ) VALUES('8');
COMMIT;

SET @@AUTOCOMMIT = 1;

但是结果很奇怪:

Users :
1
2
3

Miscs :
1
2
3
4
5
6
7
8

感谢您的帮助。

Answer 1

在应用程序中我会写这样的东西-

START TRANSACTION
TRY
  INSERT
  INSERT
  INSERT
  COMMIT
CATCH
  ROLLBACK

但是 MySQL 没有 TRY-CATCH 子句。我可以用DECLARE EXIT HANDLER这样建议你声明-

  BEGIN
    DECLARE EXIT HANDLER FOR SQLEXCEPTION  ROLLBACK;
    START TRANSACTION;
      INSERT INTO Miscs ( misc_id ) VALUES('1');
      INSERT INTO Users ( user_id ) VALUES('1');
      INSERT INTO Miscs ( misc_id ) VALUES('2');
    COMMIT;
  END;

  BEGIN
    DECLARE EXIT HANDLER FOR SQLEXCEPTION  ROLLBACK;
    START TRANSACTION;
      INSERT INTO Miscs ( misc_id ) VALUES('3');
      INSERT INTO Users ( user_id ) VALUES('2');
      INSERT INTO Miscs ( misc_id ) VALUES('4');
    COMMIT;
  END;

  BEGIN
    DECLARE EXIT HANDLER FOR SQLEXCEPTION  ROLLBACK;
    START TRANSACTION;
      INSERT INTO Miscs ( misc_id ) VALUES('5');
      INSERT INTO Users ( user_id ) VALUES('1');
      -- should stop, rollback the transaction and skip to the next/last
      INSERT INTO Miscs ( misc_id ) VALUES('6');
    COMMIT;
  END;

  BEGIN
    DECLARE EXIT HANDLER FOR SQLEXCEPTION  ROLLBACK;
    START TRANSACTION;
      INSERT INTO Miscs ( misc_id ) VALUES('7');
      INSERT INTO Users ( user_id ) VALUES('4');
      INSERT INTO Miscs ( misc_id ) VALUES('8');
    COMMIT;
  END;

从存储过程运行这段代码，因为在 MySQL 中，不可能在脚本中使用 DECLARE 处理程序。