Renames {comment}.language to {comment}.langcode.
function comment_update_8000() {
db_drop_index('comment', 'comment_nid_language');
$langcode_spec = array(
'type' => 'varchar',
'length' => 12,
'not null' => TRUE,
'default' => '',
'description' => "Language code, e.g. 'de' or 'en-US'.",
);
db_change_field('comment', 'language', 'langcode', $langcode_spec);
db_add_index('comment', 'comment_nid_langcode', array(
'nid',
'langcode',
));
}