I have a table with foreign keys. I want to change tinyint(5) to int(10).

I have:
| publishers | CREATE TABLE `publishers` (
`publisher_id` tinyint(5) unsigned NOT NULL AUTO_INCREMENT,
`market_id` tinyint(3) unsigned NOT NULL,
`name` varchar(50) NOT NULL,
`code` char(10) NOT NULL,
`timezone` varchar(50) NOT NULL DEFAULT 'Europe/Stockholm',
`status` enum('paused','active') NOT NULL DEFAULT 'active',
`created` timestamp NOT NULL DEFAULT '1971-01-01 00:00:00',
`updated` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
PRIMARY KEY (`publisher_id`),
UNIQUE KEY `UNIQUE_MARKET_ID_NAME_CODE` (`market_id`,`name`,`code`),
CONSTRAINT `publishers_ibfk_1` FOREIGN KEY (`market_id`) REFERENCES `markets` (`market_id`) ON DELETE CASCADE ON UPDATE
CASCADE
) ENGINE=InnoDB AUTO_INCREMENT=188 DEFAULT CHARSET=utf8 |

which I want to change to

| publishers | CREATE TABLE `publishers` (
`publisher_id` int(10) unsigned NOT NULL AUTO_INCREMENT,
`market_id` tinyint(3) unsigned NOT NULL,
`name` varchar(50) NOT NULL,
`code` char(10) NOT NULL,
`timezone` varchar(50) NOT NULL DEFAULT 'Europe/Stockholm',
`status` enum('paused','active') NOT NULL DEFAULT 'active',
`created` timestamp NOT NULL DEFAULT '1971-01-01 00:00:00',
`updated` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
PRIMARY KEY (`publisher_id`),
UNIQUE KEY `UNIQUE_MARKET_ID_NAME_CODE` (`market_id`,`name`,`code`),
CONSTRAINT `publishers_ibfk_1` FOREIGN KEY (`market_id`) REFERENCES `markets` (`market_id`) ON DELETE CASCADE ON UPDATE
CASCADE
) ENGINE=InnoDB AUTO_INCREMENT=188 DEFAULT CHARSET=utf8 |

when I run:
SET FOREIGN_KEY_CHECKS=0;
alter table `publishers` modify column `publisher_id` int(10) unsigned NOT NULL AUTO_INCREMENT;
SET FOREIGN_KEY_CHECKS=1;

I get:
ERROR 1025 (HY000): Error on rename of './adxsearch_2011_10_21/#sql-60de_3670d4' to './adxsearch_2011_10_21/publishers' (errno: 150)

How do I rectify this problem so I can change the column to int(10)?

Set foreign_key_checks=0 is used for insert,update,delete
not for Alter

If you want to change Parent table Column data type do below steps

1- First Identify child tables of that particular parent table
2- Delete the foreign keys associated to child table to that parent table
3- Modify the child table column data type
4- Modify the parent table column data type
5- Apply again foreign keys

Regards
Senior MySQL DBA