setup/includes/upgrades/common/2.4-principal-index.php
<?php
/**
* New Index for modAccessResourceGroup
*
* @var modX $modx
* @package setup
*/
/* add modAccessResourceGroup.principal_class index */
$class = 'modAccessResourceGroup';
$table = $modx->getTableName($class);
$sql = $driver->dropIndex($table,'principal_class');
$description = $this->install->lexicon('drop_index',array('index' => 'principal_class','table' => $table));
$this->processResults($class,$description,$sql);
$description = $this->install->lexicon('add_index',array('index' => 'principal_class','table' => $table));
$this->processResults($class, $description, array($modx->manager, 'addIndex'), array($class, 'principal_class'));