mysql数据库关于事物的问题？求解答

CREATE TABLE `t_teacher` (
  `id` int(20) NOT NULL AUTO_INCREMENT,
  `name` varchar(20) NOT NULL,
  `deposit` bigint(20) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=71 DEFAULT CHARSET=utf8;

START TRANSACTION;
SELECT * FROM t_teacher;
UPDATE t_teacher SET deposit = deposit+100 WHERE name =‘老李‘;
INSERT INTO t_teacher(id,name,deposit) VALUES (8,‘老张‘,7000);
ROLLBACK;
COMMIT;

START TRANSACTION;
SELECT * FROM t_teacher;
UPDATE t_teacher SET deposit = deposit+100 WHERE name =‘老李‘;
INSERT INTO t_teacher(name,deposit) VALUES (‘老张‘,7000);
ROLLBACK;
COMMIT;