元のphp接続データベースクエリーデータ

class Db
{
    #          
    private $conn = null;
    #          
    public function __construct($db_host='localhost',$db_user='root',$db_pwd='root',$db_name='class15_blog',$port='3306')
{
        #     
        @$this->conn = new mysqli($db_host,$db_user,$db_pwd,$db_name,$port);
        #        
        if($this->conn->connect_error){
            die('       ，  ：'.$this->conn->connect_error);
        }

        #           
        @$this->conn->query('SET NAMES UTF8');

    }

    /*
    *     
    *$db_name  string      
    */
    public function select_db($db_name){
        $this->conn->select_db($db_name);
    }
    /*
    *   、 、    
    */
    public function query($sql){
        return $this->conn->query($sql);
    }

    /*
          ，         
    */
    public function getAll($sql){
        #      
        $result  = $this->conn->query($sql);
        #           
        $data = array();
        #       
        if($result->num_rows){
            #             
            while($row = $result->fetch_assoc()){
                $data[] = $row;
            }
        }
        #  
        return $data;
    }

    /*
          
    */
    public function getOne($sql){
        #      
        $result  = $this->conn->query($sql);
        #        
        $data = '';
        #       
        if($result->num_rows){
            #          
            $data=$result->fetch_assoc();
        }
        #  
        return $data;
    }
    public function __destruct(){
        #          ，       
        if($this->conn){
            @$this->conn->close();
        }
    }
}