in mysql, on delete cascade not working

Set the foreign_key_checks to 1, I ran into this problem while exporting and importing the data during which it was set to 0

/*!40014 SET @OLD_FOREIGN_KEY_CHECKS=@@FOREIGN_KEY_CHECKS, FOREIGN_KEY_CHECKS=1 */;

If you create t2 like this it works fine:

CREATE TABLE  `t2` (
  `id` bigint(20) unsigned NOT NULL,
  `data2` text,
  PRIMARY KEY (`id`),
  CONSTRAINT `FK_t2_1` FOREIGN KEY (`id`) REFERENCES `t1` (`id`) ON DELETE CASCADE
) ENGINE=InnoDB DEFAULT CHARSET=latin1;

ETA, in answer to concerns about ugly code, the below also works:

CREATE TABLE  t2 (
  id bigint(20) unsigned NOT NULL PRIMARY KEY,
  data2 text,
  CONSTRAINT  FOREIGN KEY (id) REFERENCES t1(id) ON DELETE CASCADE
) ENGINE=InnoDB ;

The main difference is that the data type for t2.id must match that of t1.id and constraints have to be declared after the columns.