MySql错误:无法更新存储函数/触发器中的表,因为调用此存储函数/触发器的语句已使用该表
我正在运行一个MySQL查询。但是,当从表单输入添加新行时,我得到以下错误:MySql错误:无法更新存储函数/触发器中的表,因为调用此存储函数/触发器的语句已使用该表,mysql,triggers,Mysql,Triggers,我正在运行一个MySQL查询。但是,当从表单输入添加新行时,我得到以下错误: Error: Can't update table 'brandnames' in stored function/trigger because it is already used by statement which invoked this stored function/trigger. 从代码中: CREATE TRIGGER `capital` AFTER INSERT ON `brandnames`
Error: Can't update table 'brandnames' in stored function/trigger because it is
already used by statement which invoked this stored function/trigger.
从代码中:
CREATE TRIGGER `capital` AFTER INSERT ON `brandnames`
FOR EACH
ROW UPDATE brandnames
SET bname = CONCAT( UCASE( LEFT( bname, 1 ) ) , LCASE( SUBSTRING( bname, 2 ) ) )
这个错误是什么意思?正确的语法是:
FOR EACH ROW SET NEW.bname = CONCAT( UCASE( LEFT( NEW.bname, 1 ) )
, LCASE( SUBSTRING( NEW.bname, 2 ) ) )
当INSERT触发器触发时,不能更改表。插入可能会执行一些锁定,这可能会导致死锁。此外,从触发器更新表将导致在无限递归循环中再次触发相同的触发器。这两个原因都是MySQL阻止您这样做的原因 但是,根据您试图实现的目标,您可以使用new.fieldname访问新值,如果使用旧值进行更新,甚至可以使用旧值 如果您有一行名为full_brand_name,并且希望在small_name字段中使用前两个字母作为短名称,您可以使用:
CREATE TRIGGER `capital` BEFORE INSERT ON `brandnames`
FOR EACH ROW BEGIN
SET NEW.short_name = CONCAT(UCASE(LEFT(NEW.full_name,1)) , LCASE(SUBSTRING(NEW.full_name,2)))
END
我有同样的问题,并通过添加新的修复。在字段更新之前。我在这里发布了一个完整的触发器,有人想写一个触发器
DELIMITER $$
USE `nc`$$
CREATE
TRIGGER `nhachung_province_count_update` BEFORE UPDATE ON `nhachung`
FOR EACH ROW BEGIN
DECLARE slug_province VARCHAR(128);
DECLARE slug_district VARCHAR(128);
IF old.status!=new.status THEN /* neu doi status */
IF new.status="Y" THEN
UPDATE province SET `count`=`count`+1 WHERE id = new.district_id;
ELSE
UPDATE province SET `count`=`count`-1 WHERE id = new.district_id;
END IF;
ELSEIF old.province_id!=new.province_id THEN /* neu doi province_id + district_id */
UPDATE province SET `count`=`count`+1 WHERE id = new.province_id; /* province_id */
UPDATE province SET `count`=`count`-1 WHERE id = old.province_id;
UPDATE province SET `count`=`count`+1 WHERE id = new.district_id; /* district_id */
UPDATE province SET `count`=`count`-1 WHERE id = old.district_id;
SET slug_province = ( SELECT slug FROM province WHERE id= new.province_id LIMIT 0,1 );
SET slug_district = ( SELECT slug FROM province WHERE id= new.district_id LIMIT 0,1 );
SET new.prov_dist_url=CONCAT(slug_province, "/", slug_district);
ELSEIF old.district_id!=new.district_id THEN
UPDATE province SET `count`=`count`+1 WHERE id = new.district_id;
UPDATE province SET `count`=`count`-1 WHERE id = old.district_id;
SET slug_province = ( SELECT slug FROM province WHERE id= new.province_id LIMIT 0,1 );
SET slug_district = ( SELECT slug FROM province WHERE id= new.district_id LIMIT 0,1 );
SET new.prov_dist_url=CONCAT(slug_province, "/", slug_district);
END IF;
END;
$$
DELIMITER ;
希望这有助于某人A BEFORE INSERT触发器是在INSERT上实现相同表更新的唯一方法,并且只能从MySQL 5.5+中实现。但是,自动增量字段的值仅对插入后触发器可用-在插入前的情况下默认为0。因此,将编译以下示例代码,该代码将根据自动增量值id设置先前计算的代理项键值,但实际不起作用,因为NEW.id始终为0:
create table products(id int not null auto_increment, surrogatekey varchar(10), description text);
create trigger trgProductSurrogatekey before insert on product
for each row set NEW.surrogatekey =
(select surrogatekey from surrogatekeys where id = NEW.id);
@gerrit_hoekstra写道:然而,自动增量字段的值仅对插入后触发器可用-在插入前的情况下默认为0 这是正确的,但是您可以很容易地选择将由后续插入插入的自动增量字段值。这是一个有效的示例:
CREATE DEFINER = CURRENT_USER TRIGGER `lgffin`.`variable_BEFORE_INSERT` BEFORE INSERT
ON `variable` FOR EACH ROW
BEGIN
SET NEW.prefixed_id = CONCAT(NEW.fixed_variable, (SELECT `AUTO_INCREMENT`
FROM INFORMATION_SCHEMA.TABLES
WHERE TABLE_SCHEMA = 'lgffin'
AND TABLE_NAME = 'variable'));
END
你想用你的扳机做什么?表模式、示例数据和示例INSERT查询有助于lotI将注册行值的大小写更改为大写。所以我希望每次输入一行时,这个触发器都会自动为我执行此操作。我不想要javascript。@EricLeschinski我不知道他在那个问题上做了什么。MySQL说:触发器后不允许更新新行:抱歉,您需要将其从插入后更改为插入前,正如Steve在另一个SO问题中提到的回答一样,MySQL还没有?支持此功能,即使它的竞争对手支持。@Steve我也遇到了同样的问题。当我尝试时:更新employee_audit set lastName='Sharma',其中employeeNumber=112;