如何在Mysql中回滚？

Question

I want to execute multiple command to update a customer database, but I want this command to execute in a transaction, and when an error occurs in one command all changes would be rolled backed.

When I run the code in this example, if test2 table has existed the rollback has not worked and the inserted row exists in test table.

What am I doing wrong?

MySQL server is 5.1. the engine of tables is Innodb.

code example:

set autocommit = 0;
drop procedure if EXISTS rollbacktest;
delimiter //

CREATE PROCEDURE rollbacktest ()
   BEGIN

   DECLARE CONTINUE HANDLER FOR SQLEXCEPTION,SQLWARNING  SET @x2 = 4; 
   SET autocommit = 0;
   start transaction;   

    SET @x2 = 0;

insert into test(t)values (800);

CREATE TABLE `test2` (
`t`  int(11) UNSIGNED NOT NULL 
    )
ENGINE=InnoDB
DEFAULT CHARACTER SET=utf8 COLLATE=utf8_persian_ci ;


if @x2 = 4 THEN    ROLLBACK; else  commit;    end if;

   END;
//

CALL rollbacktest()

Answer 1

Your problem is that you're doing DDL ( CREATE TABLE ), which cannot be done in a transaction, so it'll implicitly commit the stuff you've done before.

This will also be the case if you tro to do DROP TABLE , ALTER TABLE , or TRUNCATE TABLE , among other things. Essentially any statement that cannot be rolled back will cause existing transactions to be auto- COMMIT ed

Answer 2

If I remember correctly, the CREATE TABLE implicitly commits the transaction.

http://dev.mysql.com/doc/refman/5.1/en/implicit-commit.html