SQL-ID字段即使在添加AUTO_INCREMENT（SQL Fiddle）后也缺少默认值

Question

我正在尝试将accountID表中的accounts字段连接到customers表中的外键。到目前为止这是我的代码：

CREATE TABLE IF NOT EXISTS `items` ( 
`id` int(6) unsigned NOT NULL,
`name` varchar(200) NOT NULL,
PRIMARY KEY (`id`) ) DEFAULT CHARSET=utf8; 

CREATE TABLE IF NOT EXISTS `accounts` ( 
`accountID` int(6) unsigned NOT NULL AUTO_INCREMENT,
`email` varchar(200) NOT NULL,
`passwordHash` varchar(200) NOT NULL,
PRIMARY KEY (`accountID`) ) DEFAULT CHARSET=utf8; 

CREATE TABLE IF NOT EXISTS `customers` ( 
`customerID` int(6) unsigned NOT NULL,
`firstName` varchar(200) NOT NULL,
`lastName` varchar(200) NOT NULL,
`address` varchar(200) NOT NULL,
`accountID` int(6) unsigned NOT NULL,
 PRIMARY KEY (`customerID`),
 CONSTRAINT `FK_accounts_accountID` FOREIGN KEY (`accountID`)
REFERENCES `accounts` (`accountID`) );

CREATE TABLE IF NOT EXISTS `orders` ( 
`id` int(6) unsigned NOT NULL,
`date` DATE NOT NULL,
`customerID` int(6) unsigned NOT NULL,
`paymentAmmount` float(6) unsigned NOT NULL,
 PRIMARY KEY (`id`),
 CONSTRAINT `FK_customers_customerID` FOREIGN KEY (`customerID`)
 REFERENCES `customers` (`customerID`) );

CREATE TABLE IF NOT EXISTS `items-orders` ( 
`id` int(6) unsigned NOT NULL,
`itemId` int(6) unsigned NOT NULL,
`orderId` int(6) unsigned NOT NULL,
`itemQuantity` int(1) unsigned NOT NULL,
PRIMARY KEY (`id`), 
KEY `FK_items_itemId` (`itemId`),
CONSTRAINT `FK_items_itemId` FOREIGN KEY (`itemId`) REFERENCES `items` 
(`id`) ) DEFAULT CHARSET=utf8; 


INSERT INTO `items` (`id`, `name`) VALUES 
('1', 'super cool huge bell'), 
('2', 'iron 20p D&D cube'),
('3', 'Dumbledore wand'),
('4', 'super cool small bell'); 

INSERT INTO `accounts` (`accountID`, `email`, `passwordHash`) VALUES
('1', 'emailAddress', 'lfadaw'),
('2', 'anotherAddress', 'dafaegdwa'),
('3', 'anotherOne', 'gaeeaw');

INSERT INTO `customers`
(`customerID`, `firstName`, `lastName`, `address`) VALUES 
('1', 'moshe', 'rubin', 'haifa'),
('2', 'tanya', 'shelomayev', 'netanya'),
('3', 'itamar', 'ofer', 'haifa'); 

INSERT INTO `orders` (`id`, `date`, `customerID`, `paymentAmmount`) VALUES 
('1', '2019-02-01', '1', '40'), 
('2', '2019-02-01', '3', '361'),
('3', '2018-10-14', '2', '10'); 

INSERT INTO `items-orders` (`id`,`itemId`,`orderId`,`itemQuantity`) VALUES 
('1', '1', '3', '2'),
('2', '4', '3', '10'),
('3', '3', '1', '1'), 
('4', '2', '2', '1'); 

我将AUTO_INCREMENT添加到accountID字段，但我仍然收到此错误消息：Field 'accountID' doesn't have a default value。

当我在表customerID和orders之间链接customers字段时，我没有收到错误。

我确定这是一个之前得到解答的问题，但我发现的只是将AUTO_INCREMENT添加到字段的提示，这对我不起作用。任何帮助将被appriciated ^^

Answer 1

这是因为你的customer表包含accountID列但约束NOT NULL并且没有默认值。

因此，实际上这是导致问题的声明：

INSERT INTO `customers`
(`customerID`, `firstName`, `lastName`, `address`) VALUES 
('1', 'moshe', 'rubin', 'haifa'),
('2', 'tanya', 'shelomayev', 'netanya'),
('3', 'itamar', 'ofer', 'haifa');