protected function cacheDatabaseIndexes($class)
    {
        if (!array_key_exists($class, $this->databaseIndexes)) {
            $this->databaseIndexes[$class] = array_merge(
                $this->buildSortDatabaseIndexes($class),
                $this->cacheDefaultDatabaseIndexes($class),
                $this->buildCustomDatabaseIndexes($class)
            );
        }
    }