mysqli将增。删。改。查询。语句封装成工具类

db.calss.php如下

<?php
 class SqlHelper{
     private $mysqli;
     private static $host='localhost'; //地址
     private static $user='root';//用户名
     private static $pwd="root";//密码
     private static $db="test";//数据库名

     public function __construct() //连接数据库，设置编码
     {
         $this->mysqli=new mysqli(self::$host,self::$user,self::$pwd,self::$db);
         if($this->mysqli->connect_error)
         {
             die("连接失败".$this->mysqli->connect_error);
         }
         $this->mysqli->query('set names utf8');
     }
     public function execute_dql($sql)//执行查询
     {
         $res=$this->mysqli->query($sql) or die("操作失败".$this->mysqli->error);
         return $res;
     }
     public function execute_dml($sql)//执行添加，删除，更新
     {
         $res=$this->mysqli->query($sql) or die("操作失败".$this->mysqli->error);
         if(!$res)
             return 0;//操作失败
         else
         {
             if($this->mysqli->affected_rows>0)
                 return 1;//操作成功
             else
                 return 2;//没有行受影响
         }
     }

 }
?>

db.php如下

<?php
 require('db.class.php');
 header("content-type:text/html;charset=utf-8");

 $SqlHelper=new SqlHelper();
 $sql="insert into user1(name,password,email,age) values ('小王',md5('987'),'[email protected]','65')";//添加
//$sql="delete from user1 where name='张三'";//删除
// $sql="update user1 set email='[email protected]' where id=1";//更新
 $res=$SqlHelper->execute_dml($sql);
 if($res==0)
     echo "操作失败";
 else
 {
     if($res==1)
         echo "操作成功";
     else
         echo "没有行受到影响";
 }

$sql="select * from user1";
$res=$SqlHelper->execute_dql($sql);//返回结果集
while($row=$res->fetch_row())
{
    foreach($row as $key=>$value)
    {
        echo "--$value";
    }
    echo "<br>";
}
?>