我有四个表:
1)Country:Two columns
a) country_id
b) country_name
2)State: Three columns
a) state_id
b) state_name
c) country_id(foreign key)
3)City: Three Columns
a) city_id
b) city_name
c) state_id(foreign key)
4) Doctor: 20 Columns
a) doc_id (primary key)
b) doc_name
c) email,gender age and so on
我已经用 dara 填充了这些表。
我在医生表中添加了三个新列:country_id、state_id 和 city_id 作为外键。
当我在该表中插入 country_id、state_id 和 city_id 作为外键时出现此错误
1452 - Cannot add or update a child row: a foreign key constraint fails (`medical_network`.`#sql-4174_45`, CONSTRAINT `#sql-4174_45_ibfk_1` FOREIGN KEY (`country_id`) REFERENCES `country` (`country_id`) ON DELETE CASCADE ON UPDATE CASCADE)
我知道这是一个基本错误,但找不到错误。
医生表:
CREATE TABLE `doctor` (
`doc_id` int(9) NOT NULL AUTO_INCREMENT,
`doc_fname` varchar(15) NOT NULL,
`doc_lname` varchar(15) NOT NULL,
`doc_province` varchar(20) NOT NULL,
`doc_city` varchar(25) NOT NULL,
`doc_gender` varchar(10) NOT NULL,
`doc_fathername` varchar(32) NOT NULL,
`doc_age` varchar(20) NOT NULL,
`doc_cnic` varchar(16) NOT NULL,
`doc_medclgname` varchar(100) NOT NULL,
`doc_specilization` varchar(100) NOT NULL,
`doc_phoneno` varchar(20) NOT NULL,
`doc_officeno` varchar(20) NOT NULL,
`doc_email` varchar(25) NOT NULL,
`doc_gradyear` int(10) NOT NULL,
`doc_licenseno` varchar(30) NOT NULL,
`doc_hosp` varchar(200) NOT NULL,
`doc_pass` varchar(35) NOT NULL,
`doc_address` varchar(100) NOT NULL,
`doc_country` varchar(100) NOT NULL,
`doc_img` varchar(200) NOT NULL,
`totime` time NOT NULL,
`fromtime` time NOT NULL,
`todate` date NOT NULL,
`fromdate` date NOT NULL,
`country_id` int(20) NOT NULL,
PRIMARY KEY (`doc_id`),
KEY `country_id` (`country_id`)
) ENGINE=InnoDB AUTO_INCREMENT=30 DEFAULT CHARSET=latin
国家表:
CREATE TABLE `country` (
`country_id` int(20) NOT NULL AUTO_INCREMENT,
`country_name` varchar(200) NOT NULL,
PRIMARY KEY (`country_id`)
) ENGINE=InnoDB AUTO_INCREMENT=252 DEFAULT CHARSET=latin1
状态表查询:
CREATE TABLE `state` (
`state_id` int(20) NOT NULL AUTO_INCREMENT,
`state_name` varchar(200) NOT NULL,
`country_id` int(20) NOT NULL,
PRIMARY KEY (`state_id`),
KEY `country_id` (`country_id`),
CONSTRAINT `state_ibfk_1` FOREIGN KEY (`country_id`) REFERENCES `country` (`country_id`) ON DELETE CASCADE ON UPDATE CASCADE
) ENGINE=InnoDB AUTO_INCREMENT=6 DEFAULT CHARSET=latin1
城市表:
CREATE TABLE `city` (
`city_id` int(20) NOT NULL AUTO_INCREMENT,
`city_name` varchar(200) NOT NULL,
`state_id` int(20) NOT NULL,
PRIMARY KEY (`city_id`),
KEY `state_id` (`state_id`),
CONSTRAINT `city_ibfk_1` FOREIGN KEY (`state_id`) REFERENCES `state` (`state_id`) ON DELETE CASCADE ON UPDATE CASCADE
) ENGINE=InnoDB AUTO_INCREMENT=10 DEFAULT CHARSET=latin1
最佳答案
首先在表中添加所有你想做外键的列。
向其中添加一些相关数据。
现在修改表并使这些新添加的列成为外键。
即 改变表表名 广告外键 (P_Id) 引用资料 ParentTable(P_Id)
关于mysql - 添加外键但出现约束违反错误,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/28105290/