Cant create a relation in mysql - Error creating foreign key on id_produk (check data types) - mysql

Question

here is my table :
CREATE TABLE `pesanan` (
`id` int(11) unsigned NOT NULL AUTO_INCREMENT,
`ref_number` varchar(50) NOT NULL DEFAULT '',
`id_produk` int(11) NOT NULL,
`id_user` int(11) NOT NULL,
`qty` int(11) NOT NULL,
`total` varchar(50) NOT NULL DEFAULT '',
`tanggal` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=10 DEFAULT CHARSET=latin1;
i want to create a relation of id_produk to table produk.id and id_user to user.id, here is the other table :
CREATE TABLE `produk` (
`id` int(11) unsigned NOT NULL AUTO_INCREMENT,
`id_kategori` int(11) NOT NULL,
`status` varchar(10) NOT NULL DEFAULT '',
`slug` varchar(100) NOT NULL DEFAULT '',
`judul` varchar(100) NOT NULL DEFAULT '',
`harga` varchar(10) DEFAULT '',
`target` int(11) DEFAULT NULL,
`desc` text,
`cover` varchar(100) DEFAULT NULL,
`tanggal` timestamp NULL DEFAULT CURRENT_TIMESTAMP,
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=29 DEFAULT CHARSET=latin1;
and user table
CREATE TABLE `user` (
`id` int(11) unsigned NOT NULL AUTO_INCREMENT,
`suspended` int(11) DEFAULT NULL,
`level` varchar(11) DEFAULT NULL,
`nama` varchar(100) DEFAULT NULL,
`email` varchar(100) DEFAULT NULL,
`password` varchar(100) DEFAULT NULL,
`alamat` text,
PRIMARY KEY (`id`),
UNIQUE KEY `email` (`email`)
) ENGINE=InnoDB AUTO_INCREMENT=23 DEFAULT CHARSET=latin1;
when i try to relation it , it give me this error :
Error creating foreign key on id_produk (check data types)

Answer 1

The columns should have the exact same data type in both tables. In your case in the "produk" and "user" tables they are unsigned, which means they go from 0 to 4294967295 but in the "pesanan" table they are signed which means they go from -2147483648 to 2147483647. See more here.
If the server allowed you to create such foreign keys, it would possibly create situations where, for example, a user is added with and ID of 2147483648 that cannot ever be referenced in the "pesanan" table.
You should change the "id_produk" and "id_user" columns in the "pesanan" table to be unsigned.