public function createIndex($collection, $columns, array $options = [])
    {
        $col = $this->db->selectCollection($collection);

        return $col->createIndex($columns, $options);
    }
public function createIndex($collection, $columns, array $options = [])
    {
        $col = $this->db->selectCollection($collection);

        return $col->createIndex($columns, $options);
    }
public function createIndex ( $ collection , $ columns , array $ options = [ ] ) { $ col = $ this -> db -> selectCollection ( $ collection ) ; return $ col -> createIndex ( $ columns , $ options ) ; }
Create new index.

@param $collection
@param $columns
@param array $options
@return string
Create new index .