Club Drupal

        'unsigned' => TRUE,

/**

 * Change {history}.nid to an unsigned int in order to match {node}.nid.

 */

function node_update_7016() {

  db_drop_primary_key('history');

  db_drop_index('history', 'nid');

  db_change_field('history', 'nid', 'nid', array(

    'description' => 'The {node}.nid that was read.',

    'type' => 'int',

    'unsigned' => TRUE,

    'not null' => TRUE,

    'default' => 0,

  ));

  db_add_primary_key('history', array('uid', 'nid'));

  db_add_index('history', 'nid', array('nid'));

}