mysqli基于面向对象的对数据的增删改查

<?php
     class SqlHelper{
private $mysqli;
private static $host="localhost";
private static $user="root";
private static $pwd="1234";
private static $db="test";


public function __construct(){
//完成初始化的任务
$this->mysqli=new 
mysqli(self::$host,self::$user,self::$pwd,self::$db);
if($this->mysqli->connect_error){
  die("连接失败".$this->mysqli->connect_error);
}
//设置访问数据库的字符集
//这句话的作用是保证php是以utf-8来操作mysql
$this->mysqli->query("set names utf8");
}


public function execute_dql(){
 
   $res=$this->mysqli->query($sql) or die("操作dql".$this->mysqli->error);
   return $res;


}


public function execute_dml($sql){
 $res=$this->mysqli->query($sql) or die("操作dql".$this->mysqli->error);
 if(!$res){
 return 0;//表示失败
 }else{
 if($this->mysqli->affected_rows>0){
  return 1;//表示成功
 }else{
return 2; //表示没有行受到影响
 }
 
 }


}


}
?>