在 MYSQL 中创建 BEFORE INSERT TRIGGER

Question

我需要帮助在 mySQL Bench 上创建 BEFORE INSERT TRIGGER。请问我是新手。

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`));

在 toy 表上创建一个 BEFORE INSERT 触发器，该触发器将记录添加到 toytracking 表中，其中包含正在插入的 toy 表记录中的信息，硬编码的 ToyAction 将是“INSERT”以及记录的当前日期和时间被插入。

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

它给我一个错误提示“错误 1054：‘新’中的未知列‘插入’”

Answer 1

摆脱IF new.inserted 测试，因为没有具有该名称的列，只需将INSERT 硬编码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

Answer 2

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 ;