mysql error 1215 cannot add foreign key contraint - mysql

Question

DROP TABLE IF EXISTS desk;
DROP TABLE IF EXISTS user;
DROP TABLE IF EXISTS authority;
CREATE TABLE authority
(
authorityId INT NOT NULL AUTO_INCREMENT PRIMARY KEY,
deskId INT DEFAULT 0,
authorityName VARCHAR(50) NOT NULL,
descriptions VARCHAR(100) NOT NULL,
userLevel TINYINT NOT NULL,
actions VARCHAR(300) DEFAULT NULL,
setDate TIMESTAMP DEFAULT CURRENT_TIMESTAMP
);
CREATE TABLE desk
(
deskId INT NOT NULL AUTO_INCREMENT PRIMARY KEY,
deskName CHAR(50) NOT NULL,
deskLink VARCHAR(100) NOT NULL,
details VARCHAR(350) DEFAULT NULL,
setDate TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
closeDate TIMESTAMP DEFAULT NULL,
userId INT DEFAULT NULL,
status TINYINT(1) DEFAULT 0
);
CREATE TABLE user
(
userId INT NOT NULL AUTO_INCREMENT PRIMARY KEY,
userName CHAR(150) NOT NULL,
password VARCHAR(500) NOT NULL,
department VARCHAR(150) DEFAULT NULL,
deskId INT NOT NULL,
status TINYINT(1) DEFAULT NULL,
userLevel TINYINT NOT NULL,
FOREIGN KEY (deskId) REFERENCES desk (deskId) ON DELETE CASCADE,
FOREIGN KEY (userLevel) REFERENCES authority (userLevel)
);
Error while executing query.
Error Code: 1215 .Cannot add foreign key contraint
I have tried many way but still cannot solve the problem, i tried change userLevel type to INT both table user and authority but nothing went to better
I really not know how to fix this problem, please help

Answer 1

Follow below steps
1) You must change your second query to
DROP TABLE IF EXISTS desk;
CREATE TABLE desk
(
deskId INT NOT NULL AUTO_INCREMENT PRIMARY KEY,
deskName CHAR(50) NOT NULL,
deskLink VARCHAR(100) NOT NULL,
details VARCHAR(350) DEFAULT NULL,
setDate TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
closeDate TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
userId INT DEFAULT NULL,
status TINYINT(1) DEFAULT 0
);
2) As your column authority.userLevel is not a primary key and you want to use it as foreign key in other table you need to create index on authority.userLevel column
use below query
ALTER TABLE `authority` ADD INDEX `UserLevelIndex` (`userLevel`);
3) Run your third query as it is to create user table

Answer 2

Run Following queries
DROP TABLE IF EXISTS desk;
DROP TABLE IF EXISTS user;
DROP TABLE IF EXISTS authority;
CREATE TABLE authority
(
authorityId INT NOT NULL AUTO_INCREMENT PRIMARY KEY,
deskId INT DEFAULT 0,
authorityName VARCHAR(50) NOT NULL,
descriptions VARCHAR(100) NOT NULL,
userLevel TINYINT NOT NULL,
actions VARCHAR(300) DEFAULT NULL,
setDate TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
index `cr_index` (userLevel)
);
CREATE TABLE desk
(
deskId INT NOT NULL AUTO_INCREMENT PRIMARY KEY,
deskName CHAR(50) NOT NULL,
deskLink VARCHAR(100) NOT NULL,
details VARCHAR(350) DEFAULT NULL,
setDate TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
closeDate TIMESTAMP DEFAULT '0000-00-00 00:00:00',
userId INT DEFAULT NULL,
status TINYINT(1) DEFAULT 0
);
CREATE TABLE `user`
(
userId INT NOT NULL AUTO_INCREMENT PRIMARY KEY,
userName CHAR(150) NOT NULL,
password VARCHAR(500) NOT NULL,
department VARCHAR(150) DEFAULT NULL,
deskId INT NOT NULL,
status TINYINT(1) DEFAULT NULL,
userLevel TINYINT NOT NULL,
FOREIGN KEY (deskId) REFERENCES desk (deskId) ON DELETE CASCADE,
FOREIGN KEY (userLevel) REFERENCES authority (userLevel)
);
In your query you write timestamp default value NULL and you can create a non index key userLevel as a foreign key so from your query remove default value or change the default value 0000-00-00 00:00:00(in desk table) and add index in userLevel column (in authority table)
I hope this will work for you