在MYSQL中创建BEFORE INSERT触发器
问题描述:
我需要帮助在mySQL Bench上创建BEFORE INSERT触发器。即时通讯新的这个请。在MYSQL中创建BEFORE INSERT触发器
CREATE TABLE `quincyninying`.`toytracking` (
`Toyid` INT NOT NULL,
`ToyName` VARCHAR(50) NULL,
`Toycost` DECIMAL NULL,
`ToyAction` VARCHAR(50) NULL,
`ActionDate` DATETIME NULL,
PRIMARY KEY (`Toyid`));
CREATE TABLE `quincyninying`.`toy` (
`Toyid` INT NOT NULL,
`ToyName` VARCHAR(50) NULL,
`Toycost` DECIMAL NULL,
PRIMARY KEY (`Toyid`));
创建上,增加了一个记录到toytracking表从玩具表记录正被插入的信息,硬编码ToyAction,这将是“插入”和当前日期的玩具表中的BEFORE INSERT触发器并记录插入的时间。
ERROR 1054: Unknown column 'inserted' in 'NEW' SQL Statement:
CREATE DEFINER = CURRENT_USER TRIGGER `quincyninying`.`toy_BEFORE_INSERT` BEFORE INSERT ON `toy`
FOR EACH ROW
BEGIN
IF new.inserted THEN
SET @toyaction = 'DELETE';
ELSE
SET @toyaction = 'NEW';
END IF;
INSERT INTO `quincyninying`.`toytracking` (toyId, ToyName, ToyCost, Toyaction, ActionDate)
VALUES (new.toyid, new.Toyname, new.Toycost,@Toyaction, now());
END
这引发了我一个错误说“错误1054:在‘插入’未知列‘新’”
答
摆脱IF new.inserted
测试,因为有这个名字没有列,只是硬代码INSERT
作为您在要求中所述的ToyAction
列的值。
CREATE DEFINER = CURRENT_USER TRIGGER `quincyninying`.`toy_BEFORE_INSERT` BEFORE INSERT ON `toy`
FOR EACH ROW
BEGIN
INSERT INTO `quincyninying`.`toytracking` (toyId, ToyName, ToyCost, Toyaction, ActionDate)
VALUES (new.toyid, new.Toyname, new.Toycost, 'INSERT', now());
END
+0
谢谢你,巴尔玛。这与SQL完全不同。我是MySQL的新手。如果是BEFORE UPDATE触发器,请给我举个例子吗?谢谢! – ninying90
答
试试这个:
DELIMITER $$
CREATE
TRIGGER toy_before_insert BEFORE INSERT
ON toy
FOR EACH ROW BEGIN
IF NEW.Toyaction THEN
SET @Toyaction = 'DELETE';
ELSE
SET @Toyaction = 'NEW';
END IF;
INSERT INTO toytracking (toyId, ToyName, ToyCost, Toyaction, ActionDate) VALUES (NEW.Toyid, NEW.ToyName, NEW.ToyCost, @Toyaction, NOW());
END$$
DELIMITER ;
这是很清楚的。 'TOY'表中没有名为'inserted'的列。你想达到什么?而且,你的餐桌设计并不常见。这两张表格之间有冗余信息。 – Hermanto
我想玩玩具桌上的BEFORE INSERT触发器,该玩具桌上的玩具表记录正在被INSERTED,硬编码ToyAction的信息添加到玩具跟踪表中,该玩具表将被'INSERT'和当前日期和时间记录被插入。 – ninying90
什么是'IF new.inserted'应该测试? – Barmar