解析在PHP中使用mysqli扩展库对mysql的操作

header("Content-type: text/html;charset=utf-8");
//mysqli操作mysql数据库(面向对象方式)
//1、创建MySQLi对象
$mysqli =new MySQLi("localhost","root","test");
if($mysqli->connect_error){
die("连接失败".$mysqli->connect_error);
}
//2、操作数据库（发送sql）
$sql="select *from user1";
//3、处理结果
$res =$mysqli->query($sql);
//var_dump($res);
//fetch_assoc fetch_array fetch_object
while($row=$res->fetch_row()){
var_dump($row);
/* foreach($row as $val){
echo '--'.$val;
}
echo '
';*/
}
//4、关闭资源
$res->free();
$mysqli->close();
?>

header("Content-type: text/html;charset=utf-8"); $mysqli=mysqli_connect("localhost","test");
if(!$mysqli){
die("连接失败".mysqli_connect_error());
}
$sql="select *from user1";
$res=mysqli_query($mysqli,$sql);
//var_dump($res);
while($row=mysqli_fetch_row($res)){ foreach ($row as $val){ echo '-'.$val;
}
echo '
';
}
//释放内存
mysqli_free_result($res);
mysqli_close($mysqli);
?>

header("Content-type: text/html;charset=utf-8");
$mysqli = new MySQLi("localhost","test");
if($mysqli->connect_error){
die("连接失败".$mysql->connect_error);
}
//增加一条记录
//$sql="insert into user1 (name,password,email,age) values ('lucy',md5('lucy'),'lucy@163.com',17)";
//删除一条记录
//$sql="delete from user1 where id =80";
//更新一条记录
$sql="update user1 set age=20 where id=7";
$res=$mysqli->query($sql);
if(!$res){
echo "操作失败".$mysqli->error;
}else{
if($mysqli->affected_rows>0){
echo "成功";
}else{
echo "没有行受影响";
}
}
//关闭资源
$mysqli->close();
?>

class SqlHelper{ private $mysqli;
//这里先写死，以后写死的东西用一个文件来配置
private static $host="localhost";
private static $user="root";
private static $pwd="root";
private static $db="test";
public function __construct(){ $this->mysqli=new MySQLi(self::$host,self::$user,self::$pwd,self::$db);
if($this->mysqli->connect_error){
die("连接失败".$this->mysqli->connect_error);
}
//设置字符集
$this->mysqli->query("set names utf8");
}
//dql operate
function execute_dql($sql){
$res =$this->mysqli->query($sql) or die($this->mysqli->error);
return $res;
}
//dml operate
function execute_dml($sql){
$res =$this->mysqli->query($sql) or die($this->mysqli->error); if(!$res){
return 0;//失败
}else{
if($this->mysqli->affected_rows>0){
return 1;//成功
}else{
return 2;//没有行到影响
}
}
}
}
?>