CREATE TRIGGER trigger_name {BEFORE | AFTER | INSTEAD OF} triggering_event ON table_name [FOR EACH ROW] | [FOR EACH STATEMENT] trigger_body; 1. 2. 3. 4. 其中: CREATE TRIGGER表示创建一个触发器,trigger_name是触发的名称; BE
(5)for each row:这个声明用来指定受触发事件影响的每一行,都要激活触发器的 动作。目前MySQL仅支持行级触发器,不支持语句级别的触发器(例如createtable 等语句)。for each row表示更新(insert、update或者delete)操作影响每一条记录都会执行一次触发程序。 (6)trigger_statement:当触发程序激活时执行的语句。如果执行...
1.MYSQL 不支持语句触发(for each statement),只支持行触发(for each row,新旧数据通过关键字new和old区别) 实验: 数据库存储和触发器实验 一、实验目的 理解,实现并逐渐熟悉存储过程的使用 存储过程(Stored Procedure)是指一组可编程的函数,是为了完成特定功能的SQL语句集,经编译创建并保存在数据库中,用户可通过...
4.MySQL5.0的版本,所有的触发器都是基于行(FOR EACH ROW)的,因为触发器通过insert,update,delete激活,MySQL5.0不支持FOR EACH STATEMENT,如: DELIMITER $$ DROPTRIGGER/*!50032 IF EXISTS*/`test`.`tai_a`$$ CREATE /*!50017 DEFINER = 'mysqldba'@'%'*/ TRIGGER`tai_a` AFTERINSERTON`a` FOREACH ROW...
报错2:Error Code: 1442. Can't update table 'student' in stored function/trigger because it is already used by statement which invoked this stored function/trigger. 原因:存储的函数或触发器不能修改已被调用该函数或触发器的语句(用于读取或写入)使用的表。
FOR EACH ROW trigger_stmt 其中: trigger_name:标识触发器名称,用户自行指定; trigger_time:标识触发时机,取值为 BEFORE 或 AFTER; trigger_event:标识触发事件,取值为 INSERT、UPDATE 或 DELETE; tbl_name:标识建立触发器的表名,即在哪张表上建立触发器; ...
13.1.20 CREATE TRIGGER Statement CREATE [DEFINER = user] TRIGGER trigger_name trigger_time trigger_event ON tbl_name FOR EACH ROW [trigger_order] trigger_body trigger_time: { BEFORE | AFTER } trigger_event: { INSERT | UPDATE | DELETE } trigger_order: { FOLLOWS | PRECEDES } other_trigger...
(1)Trigger表示触发器的名称,这里有两个触发器分别是tri_student和trigger_student (2)Event表示激活触发器的事件,这里的两个触发事件为插入操作INSERT (3)Table表示激活触发器的操作对象表,这里都为student表 (4)Statement表示激活触发器之后执行的语句
which occurs once for each row affected by the triggering event. In the example, the trigger body is a simpleSETthat accumulates into a user variable the values inserted into theamountcolumn. The statement refers to the column asNEW.amountwhich means“the value of theamountcolumn to be inserted...
以下是MariaDB中create trigger的语法:MySQL不支持or replace和if not exists子句。 CREATE [OR REPLACE] TRIGGER [IF NOT EXISTS] trigger_name { BEFORE | AFTER } { INSERT | UPDATE | DELETE } ON tbl_name FOR EACH ROW trigger_body 触发器只能建立在永久表上,不能建立在视图和临时表上。MySQL/Maria...