<?php
global $wpdb;

$keys = $wpdb->get_results( "SHOW KEYS FROM `{$wpdb->prefix}icl_translations` WHERE `Column_name`='trid' AND `Key_name`<>'trid_lang'" );
if ( empty( $keys ) ) {
	$sql = "ALTER TABLE `{$wpdb->prefix}icl_translations` ADD KEY `trid` (`trid`)";
	$wpdb->query( $sql );
}

$sql = "ALTER TABLE `{$wpdb->prefix}icl_languages` ADD tag VARCHAR(8)";
$wpdb->query( $sql );
$sql = "UPDATE `{$wpdb->prefix}icl_languages` SET tag = REPLACE(default_locale, '_', '-')";
$wpdb->query( $sql );
icl_cache_clear();