我們如何從兩張表中找出參考？ MySQL的

Question

這是我的表

CREATE TABLE IF NOT EXISTS `carslibrary` (
    `CarID` int(10) unsigned NOT NULL AUTO_INCREMENT, 
    `CarName` varchar(255) NOT NULL, 
    PRIMARY KEY (`CarID`) 
) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=12 ; 

CREATE TABLE IF NOT EXISTS `colorslibrary` (
    `ColorID` int(11) unsigned NOT NULL AUTO_INCREMENT, 
    `ColorName` varchar(255) NOT NULL, 
    PRIMARY KEY (`ColorID`) 
) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=7 ; 

我想創建另一個表參照CarID和ColorID

我做facerecord命名

CREATE TABLE IF NOT EXISTS `facerecord` (
    `carslibrary_ID` int(10) NOT NULL, 
    `colorslibrary_ID` int(11) NOT NULL, 
    KEY `carslibrary_ID` (`carslibrary_ID`), 
    KEY `colorslibrary_ID` (`colorslibrary_ID`) 
) ENGINE=InnoDB DEFAULT CHARSET=latin1; 

我收到此錯誤

表

Error creating foreign key on carslibrary_ID (check data types) 

Error creating foreign key on colorslibrary_ID (check data types) 

Error 
ALTER TABLE `facerecord` ADD FOREIGN KEY ( `carslibrary_ID`) REFERENCES `cars2`.`carslibrary` (
`CarID` 
) ON DELETE SET NULL ON UPDATE SET NULL ; 

ALTER TABLE `facerecord` ADD FOREIGN KEY ( `colorslibrary_ID`) REFERENCES `cars2`.`colorslibrary` (
`ColorID` 
) ON DELETE SET NULL ON UPDATE SET NULL ; 

Answer 1

您在該喲中有不匹配的數據類型你的主表使用unsigned整數類型，但你的facerecord表使用普通簽名INT(10), INT(11)作爲數據類型。

更改facerecord到：

CREATE TABLE IF NOT EXISTS `facerecord` (
    `carslibrary_ID` int(10) unsigned NOT NULL, 
    `colorslibrary_ID` int(11) unsigned NOT NULL, 
    KEY `carslibrary_ID` (`carslibrary_ID`), 
    KEY `colorslibrary_ID` (`colorslibrary_ID`) 
) ENGINE=InnoDB DEFAULT CHARSET=latin1; 

Answer 2

CarId和ColorId是無符號整數，所以你應該使用：

CREATE TABLE IF NOT EXISTS `facerecord` (
    `carslibrary_ID` int(10) unsigned NOT NULL, 
    `colorslibrary_ID` int(11) unsigned NOT NULL, 
    KEY `carslibrary_ID` (`carslibrary_ID`), 
    KEY `colorslibrary_ID` (`colorslibrary_ID`) 
) ENGINE=InnoDB DEFAULT CHARSET=latin1;