Error No 150 mySQL

Question

This is making me sweat - I am getting error 150 when I try and create a table in mySQL. I've scoured the forums to no avail. The statement uses foreign key constraints - both tables are InnoDB, all relevant columns have the same data type and both tables have the same charset and collation. Here's the CREATE TABLE and the original CREATE TABLE statement for the table that's being referenced. Any ideas?

New table:

CREATE TABLE `approval` (
  `rev_id` int(10) UNSIGNED NOT NULL,
  `rev_page` int(10) UNSIGNED NOT NULL,
  `user_id` int(10) UNSIGNED NOT NULL,
  `date` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
  PRIMARY KEY  (`rev_id`,`rev_page`,`user_id`),
  KEY `FK_approval_user` (`user_id`),
  CONSTRAINT `FK_approval_revision` FOREIGN KEY (`rev_id`, `rev_page`) REFERENCES `revision` (`rev_id`, `rev_page`),
  CONSTRAINT `FK_approval_user` FOREIGN KEY (`user_id`) REFERENCES `user` (`user_id`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1;

Referenced table:

CREATE TABLE `revision` (
  `rev_id` int(10) unsigned NOT NULL auto_increment,
  `rev_page` int(10) unsigned NOT NULL,
  `rev_text_id` int(10) unsigned NOT NULL,
  `rev_comment` tinyblob NOT NULL,
  `rev_user` int(10) unsigned NOT NULL default '0',
  `rev_user_text` varbinary(255) NOT NULL default '',
  `rev_timestamp` binary(14) NOT NULL default '\0\0\0\0\0\0\0\0\0\0\0\0\0\0',
  `rev_minor_edit` tinyint(3) unsigned NOT NULL default '0',
  `rev_deleted` tinyint(3) unsigned NOT NULL default '0',
  `rev_len` int(10) unsigned default NULL,
  `rev_parent_id` int(10) unsigned default NULL,
  PRIMARY KEY  (`rev_id`),
  UNIQUE KEY `rev_page_id` (`rev_page`,`rev_id`),
  KEY `rev_timestamp` (`rev_timestamp`),
  KEY `page_timestamp` (`rev_page`,`rev_timestamp`),
  KEY `user_timestamp` (`rev_user`,`rev_timestamp`),
  KEY `usertext_timestamp` (`rev_user_text`,`rev_timestamp`)
) ENGINE=InnoDB AUTO_INCREMENT=4904 DEFAULT CHARSET=binary MAX_ROWS=10000000 AVG_ROW_LENGTH=1024;

Answer 1

This error is typically related to foreign key restrictions. Execute show innodb status and look for the LATEST FOREIGN KEY ERROR section to get some more concrete explanation.

This is what I get when creating the second table:

Error in foreign key constraint of table test/approval: FOREIGN KEY (rev_id, rev_page) REFERENCES revision (rev_id, rev_page),
CONSTRAINT FK_approval_user FOREIGN KEY (user_id) REFERENCES user (user_id) ) ENGINE=InnoDB DEFAULT CHARSET=latin1: Cannot find an index in the referenced table where the referenced columns appear as the first columns, or column types in the table and the referenced table do not match for constraint.