MySQL: referencing foreign keys - mysql

Question

I am trying to reference a foreign key to its parent key in mysql and i get an awkward error.
I have tried the following.
ALTER TABLE `website`
ADD CONSTRAINT `website_cms_fk1` FOREIGN KEY (`cms_id`) REFERENCES `cms_technology` (`ID`);
also
ALTER TABLE website ADD FOREIGN KEY (cms_id) REFERENCES cms_technology (ID)
And I get the following error.
*#1005 - Can't create table 'script.#sql-5203_110b8ba' (errno: 150)*
The following is my tables
CREATE TABLE IF NOT EXISTS `cms_technology` (
`ID` bigint(20) unsigned NOT NULL AUTO_INCREMENT,
`cms_name` varchar(250) NOT NULL DEFAULT '',
`cms_description` varchar(250) NOT NULL DEFAULT '',
PRIMARY KEY (`ID`)
);
INSERT INTO `cms_technology` (`ID`, `cms_name`, `cms_description`) VALUES
(1, 'Wordpress', 'WordPress › Blog Tool, Publishing Platform, and CMS');
CREATE TABLE IF NOT EXISTS `website` (
`ID` bigint(20) unsigned NOT NULL AUTO_INCREMENT,
`website_url` varchar(60) NOT NULL DEFAULT '',
`website_ip` varchar(20) NOT NULL DEFAULT '',
`website_title` varchar(250) NOT NULL DEFAULT '',
`website_status` varchar(10) NOT NULL DEFAULT '',
`website_scanned` datetime NOT NULL DEFAULT '0000-00-00 00:00:00',
`website_response` int(3) NOT NULL DEFAULT '0',
`cms_id` int(5) NOT NULL DEFAULT '0',
PRIMARY KEY (`ID`)
);
INSERT INTO `website` (`ID`, `website_url`, `website_ip`, `website_title`, `website_status`, `website_scanned`, `website_response`, `website_cms`) VALUES
(1, 'http://www.wpbeginner.com/', '', '', '', '0000-00-00 00:00:00', 0, 0);
What im I doing wrong?

Answer 1

you need to change the data type of the of column cms_ID from table website in order to reference table cms_technology. The properties of the to columns must be the same.
CREATE TABLE IF NOT EXISTS `website` (
`ID` bigint(20) unsigned NOT NULL AUTO_INCREMENT,
`website_url` varchar(60) NOT NULL DEFAULT '',
`website_ip` varchar(20) NOT NULL DEFAULT '',
`website_title` varchar(250) NOT NULL DEFAULT '',
`website_status` varchar(10) NOT NULL DEFAULT '',
`website_scanned` datetime NOT NULL DEFAULT '0000-00-00 00:00:00',
`website_response` int(3) NOT NULL DEFAULT '0',
`cms_id` bigint(20) unsigned NOT NULL, -- <<== HERE
PRIMARY KEY (`ID`)
);
SQLFiddle Demo

Answer 2

I was missing the KEY cms_id (cms_id)
CREATE TABLE IF NOT EXISTS `website` (
`ID` bigint(20) unsigned NOT NULL AUTO_INCREMENT,
`website_url` varchar(60) NOT NULL DEFAULT '',
`website_ip` varchar(20) NOT NULL DEFAULT '',
`website_title` varchar(250) NOT NULL DEFAULT '',
`website_status` varchar(10) NOT NULL DEFAULT '',
`website_scanned` datetime NOT NULL DEFAULT '0000-00-00 00:00:00',
`website_response` int(3) NOT NULL DEFAULT '0',
`cms_id` bigint(20) unsigned NOT NULL DEFAULT '0',
PRIMARY KEY (`ID`),
KEY `cms_id` (`cms_id`)
);
ALTER TABLE `website`
ADD CONSTRAINT `website_cms_fk1` FOREIGN KEY (`cms_id`) REFERENCES `cms_technology` (`ID`);