我有一个调用生成过程的事务,但是如果在该过程之后发生错误,我会注意到该过程期间和之前的语句已被提交。程序如下:
DELIMITER $$
CREATE PROCEDURE location_processor(in _city varchar(20), in _country_code varchar(2), out id int)
begin
select location_id into id from location where city = _city and country_code = _country_code limit 0,1;
if id is null then
select @id := max(location_id) from location;
if @id is null then
set @id = 0;
end if;
set @id = @id + 1;
insert into location (location_id, city, country_code)
values(@id, _city, _country_code);
set id = @id;
end if;
end; $$
DELIMITER ;
注意:此过程中没有使用开始/结束事务语法;尽管我有理由相信过程本身的开始和结束导致提交为:
Note:
Within all stored programs (stored procedures and functions, triggers, and events), the parser treats BEGIN [WORK] as the beginning of a BEGIN ... END block. Begin a transaction in this context with START TRANSACTION instead.
( https://dev.mysql.com/doc/refman/5.7/en/commit.html )
我需要此过程来进行错误检查。无论如何,在使用事务中的过程时是否可以避免在事务中提交?
最佳答案
通过一个简单的例子,我无法重现该问题:
mysql> DROP PROCEDURE IF EXISTS `location_processor`;
Query OK, 0 rows affected (0.00 sec)
mysql> DROP TABLE IF EXISTS `location`;
Query OK, 0 rows affected (0.00 sec)
mysql> CREATE TABLE IF NOT EXISTS `location` (
-> `location_id` INT,
-> `city` VARCHAR(255),
-> `country_code` VARCHAR(255)
-> );
Query OK, 0 rows affected (0.00 sec)
mysql> DELIMITER //
mysql> CREATE PROCEDURE `location_processor`()
-> BEGIN
-> INSERT INTO `location`
-> (`location_id`, `city`, `country_code`)
-> VALUES
-> (2, 'city', 'country_code');
-> END//
Query OK, 0 rows affected (0.00 sec)
mysql> DELIMITER ;
mysql> START TRANSACTION;
Query OK, 0 rows affected (0.00 sec)
mysql> SELECT `location_id`, `city`, `country_code`
-> FROM `location`;
Empty set (0.00 sec)
mysql> INSERT INTO `location`
-> (`location_id`, `city`, `country_code`)
-> VALUES
-> (1, 'city', 'country_code');
Query OK, 1 row affected (0.00 sec)
mysql> CALL `location_processor`;
Query OK, 1 row affected (0.00 sec)
mysql> INSERT INTO `location`
-> (`location_id`, `city`, `country_code`)
-> VALUES
-> (3, 'city', 'country_code');
Query OK, 1 row affected (0.00 sec)
mysql> SELECT `location_id`, `city`, `country_code`
-> FROM `location`;
+-------------+------+--------------+
| location_id | city | country_code |
+-------------+------+--------------+
| 1 | city | country_code |
| 2 | city | country_code |
| 3 | city | country_code |
+-------------+------+--------------+
3 rows in set (0.00 sec)
mysql> ROLLBACK;
Query OK, 0 rows affected (0.00 sec)
mysql> SELECT `location_id`, `city`, `country_code`
-> FROM `location`;
Empty set (0.00 sec)
关于MySQL:事务内的过程调用导致提交,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/43441388/