錯誤1452：無法添加或更新子行

Question

我有一個奇怪的問題，我試圖添加一個外鍵引用另一個表，但它由於某種原因失敗。由於我對MySQL的知識有限，唯一可能會懷疑的是在引用我想引用的表的不同表上有一個外鍵。

這裏是我的表關係的照片，通過工作臺產生的：關係

CREATE TABLE `beds` (
    `bedId` int(11) NOT NULL, 
    `wardId` int(11) DEFAULT NULL, 
    `depId` int(11) DEFAULT NULL, 
    `desc` varchar(45) DEFAULT NULL, 
    PRIMARY KEY (`bedId`), 
    KEY `departmentId_idx` (`depId`), 
    KEY `wardId_idx` (`wardId`), 
    CONSTRAINT `departmentId` FOREIGN KEY (`depId`) 
    REFERENCES `department` (`Department_Id`) 
    ON DELETE NO ACTION ON UPDATE NO ACTION, 
    CONSTRAINT `wardId` FOREIGN KEY (`wardId`) REFERENCES `wards` (`wardId`) 
    ON DELETE NO ACTION ON UPDATE NO ACTION 
) ENGINE=InnoDB DEFAULT CHARSET=latin1$$ 

---

ERROR 1452: Cannot add or update a child row: a foreign key constraint fails 
(`asiahospitaldb`.`beds`, CONSTRAINT `departmentId` FOREIGN KEY (`depId`) 
REFERENCES `department` (`Department_Id`) 
ON DELETE NO ACTION ON UPDATE NO ACTION) 

SQL Statement: 

INSERT INTO `asiahospitaldb`.`Beds` (`bedId`, `wardId`, `depId`, `desc`) 
VALUES ('456', '7444', '4555', 'ikiuj') 

---

Answer 1

這

ERROR 1452: Cannot add or update a child row: a foreign key constraint 
fails (`asiahospitaldb`.`beds`, CONSTRAINT `departmentId` FOREIGN KEY 
(`depId`) REFERENCES `department` (`Department_Id`) ON DELETE NO 
`enter code here`ACTION ON UPDATE NO ACTION) 

告訴您，您插入的行對於您插入列depId（如Omesh指出的）中的值的department/department_id需要相應的值。最重要的一點是在這裏：

（DEPID）參考系（DEPARTMENT_ID）

換句話說，你已經嘗試在一個不存在的部門創建一張牀。