public function insertNode($ancestorId, $descendantId)
    {
        $table = $this->getPrefixedTable();
        $ancestor = $this->getAncestorColumn();
        $descendant = $this->getDescendantColumn();
        $depth = $this->getDepthColumn();

        $query = "
            INSERT INTO {$table} ({$ancestor}, {$descendant}, {$depth})
            SELECT tbl.{$ancestor}, {$descendantId}, tbl.{$depth}+1
            FROM {$table} AS tbl
            WHERE tbl.{$descendant} = {$ancestorId}
            UNION ALL
            SELECT {$descendantId}, {$descendantId}, 0
        ";

        DB::connection($this->connection)->statement($query);
    }