public function alterColumn($table, $column, $type)
    {
        $time = $this->beginCommand("alter column $column in table $table to $type");
        $this->db->createCommand()->alterColumn($table, $column, $type)->execute();
        if ($type instanceof ColumnSchemaBuilder && $type->comment !== null) {
            $this->db->createCommand()->addCommentOnColumn($table, $column, $type->comment)->execute();
        }
        $this->endCommand($time);
    }