create table laruence(
    id int unsigned auto_increment,title varchar(225) not null default '',link varchar(id),unique key link_idx(link)
)engine=innodb charset=utf8mb4;

                        $this->pdo = new \PDO($this->dsn,$this->user,$this->password,array(
                                                \PDO::ATTR_PERSISTENT => $this->persistent
                                                )); 
                        $this->pdo->setAttribute( \PDO::ATTR_ERRMODE,\PDO::ERRMODE_EXCEPTION);
                        $this->pdo->exec("set names utf8mb4");