mysqli class (no transaction precompilation)

host=isset($arr['host'])?$arr['host']:'localhost';
        $this->user=isset($arr['$password'])?$arr['user']:'root';
        $this->password=isset($arr['password'])?$arr['password']:'759114';
        $this->charset=isset($arr['charset'])?$arr['charset']:'utf8';
        $this->dbname=isset($arr['dbname'])?$arr['dbname']:'project';

        $this->mysqli= new mysqli($this->host,$this->user,$this->password,$this->dbname);

    }


    #对sql语句进行判断
    private function  exec($sql){
        if(!($this->mysqli->query($sql))){
            die($this->mysqli->error);                     #错误处理
        }
        return $this->mysqli->query($sql);
    }

    #数据的操作
    public function  db_delete($sql){
        $this->exec($sql); 
        echo "您的sql语句错误:
";                         #执行exec()
        return $this->mysqli->affected_rows;        #获取受影响的行数
    }

    #数据更新操作
    public  function  db_update($sql){
        $this->exec($sql);                          #执行exec()
        return $this->mysqli->affected_rows;        #获取受影响的行数
    }

    #插入操作
    public function  db_insert($sql){
        $res = $this->exec($sql);                          #执行exec()
        return $this->mysqli->affected_rows;        #获取受影响的行数
    
    }

    #获取单条数据
    public function db_getOne($sql){
        $res = $this->exec($sql);
        return $res = $res->fetch_assoc();
    }

    #获取多条数据
    public function db_getAll($sql){
        $res = $this->exec($sql);
        return $res->fetch_all();
    }

}