有效沟通问答-【官方】百战程序员_IT在线教育培训机构

<?php
echo '<pre>';
   $con=mysqli_connect('localhost','root','','beixidb');
   if($con){
   mysqli_query($con,"set names utf8");
   mysqli_query($con,"set character_set_client=utf8");
   mysqli_query($con,"set character_set_results=utf8");



   $sql = 'select * form student where 1';
   $result=$con->query($sql);
   print_r($result);
   }else{
   echo '失败';
   }

 ?>

Parse error: syntax error, unexpected 'if' (T_IF) in E:\xampp\htdocs\code\数据库\php数据库连接.php on line 3

老师我找不到哪里出错了

WEB前端全系列/第五阶段：前后端交互/PHP、数据库编程与设计 37楼

index.php

<?php
//获取数据库中的数据
try{
    $con=new PDO("mysql:host=localhost;dbname=beixidb;charset=utf8;port=3306",'root','');
    $con->setAttribute(PDO::ATTR_ERRMODE,PDO::ERRMODE_EXCEPTION);
    $res=$con->query('select * from news');
    $data=$res->fetchAll(PDO::FETCH_ASSOC);
    // print_r($data);
    //字符串的拼接
    $str='';
    for($i=0;$i<count($data);$i++){
        $str.="<tr><td>{$data[$i]['id']}</td><td>{$data[$i]['title']}</td><td>{$data[$i]['author']}</td><td>{$data[$i]['des']}</td>
        <td>{$data[$i]['content']}</td><td>{$data[$i]['time']}</td><td><a href='#'>删除</a></br><a href='#'>修改</a></td></tr>";
    }
}catch(PDOException $e){
    echo $e->getMessage();
}

?>

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .container{
            width:800px;
            height:600px;
            margin:20px auto;
            border:1px solid #ccc;
            overflow:hidden;
        }
        .left,.right{
            float:left;
        }
        .left{
            width:120px;
        }
        table{
            width:620px;
        }
        .left a{
            display:block;
            text-decoration:none;
            color:#000;
            padding:10px 0;
            border-bottom:1px solid #efefef;
        }
    </style>
</head>
<body>
    <div class="container">
        <div class="left">
            <a href="">所有文档列表</a>
            <a href="添加文档.html">添加列表</a>
        </div>
        <div class="right">
        <table border="1" cellpadding="0" cellspacing="0" width="600">
        <tr>
            <th>ID</th>
            <th>标题</th>
            <th>作者</th>
            <th>简介</th>
            <th>时间</th>
            <th>操作</th>
        </tr>
        <?php echo $str?>
    </table>
        </div>
    </div>
</body>
</html>

添加文档.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .container{
            width:800px;
            margin:20px auto;
            border:1px solid #ccc;
            overflow:hidden;
        }
        .left,.right{
            float:left;
        }
        .left{
            width:120px;
        }
        input{
            width: 500px;
        }
        .left a{
            display:block;
            text-decoration:none;
            color:#000;
            padding:10px 0;
            border-bottom:1px solid #efefef;
        }
        textarea{
            vertical-align: top;
            margin-top: 5px;
            width: 500px;
            resize: none;
        }
        .btn{
            display: block;
            width: 80px;
            height: 50px;
            border: none;
            background: orange;
            border-radius: 5px;
            color: #fff;
            margin: 10px auto;
            cursor: pointer;
        }
    </style>
</head>
<body>
    <div class="container">
        <div class="left">
            <a href="#">添加文档页面</a>
        </div>
        <div class="right">
            <form action="addnews.php" method="get">
                标题:<input type="text" name="title"><br/>
                作者:<input type="text" name="author"><br/>
                简介:<input type="text" name="des"><br/>
                内容:<textarea type="text" name="content" cols="30" rows="10"></textarea><br/>
                <input type="submit" value="保存" class="btn">
            </form>
        </div>
    </div>
</body>
</html>

addnews.php

<?php
    echo '<pre>';
//接收用户传来的数据
    $title=isset($_GET['.title'])?$_GET['title']:'';
    $author=isset($_GET['.author'])?$_GET['author']:'';
    $des=isset($_GET['.des'])?$_GET['des']:'';
    $content=isset($_GET['.content'])?$_GET['content']:'';
    //生成一个时间戳
    $time=time();
    //写入数据库


    $con=new PDO("mysql:host=localhost;dbname=beixidb;charset=utf8;port=3306",'root','');
    $res=$con->query("insert into news (title,author,des,content,time) values('{$title}','$author','$des','$content','$time')");
    if($res){
        echo '<script> alert("添加成功");window.location.href="index.php"</script>';
    }
    else{
        echo '添加失败';
    }
?>

老师，为什么这个案例添加成功后标题作者等信息不显示，只显示时间戳，是没添加进去吗？具体代码如上：

效果图附下：

WEB前端全系列/第五阶段：前后端交互/PHP、数据库编程与设计 38楼

老师那里写错了为啥前台没有返回来的数据？？？？？

<?php
$succesArr=array('msg'=>'ok','info'=>'sorry');
echo json_decode($succesArr);

?>

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script src="jquery-1.8.3(1).js"></script>
</head>
<body>
    <span>用户名：</span><input type="text" class="uname" >
    <span>密码：  </span><input type="password" class="pass_input">
    <button>get无参请求</button>
    <button>post请求</button>
    <script>
        var $use_input=$('.uname');
       var $pass_inout=$('.pass_inout');
       var $btn=$('button');
       $btn.eq(0).click(function(){
           $.ajax(
              {
                  type:'get',
                  url:'011data.php',
                  dataType:'json',
                  success:function(res){
                      console.log(res);
                  }
              }
           )
       });
    </script>
</body>
</html>

WEB前端全系列/第五阶段：前后端交互/PHP、数据库编程与设计 39楼

ie浏览器怎么办

WEB前端全系列/第五阶段：前后端交互/网络请求AJAX 40楼

<?php
echo '<pre>';
// $pdo=new PDO('mysql:host=localhost;dbname=beixi','Hunter','Hunter009723');
// 案例2 PDO里提供了一种方式去确保连接是否成功 try...catch
try{
    echo '<pre>';
    $pdo=new PDO('mysql:host=localhost;dbname=beixdi','Hunter','Hunter009723');
    print_r($pdo);
}
catch(PDOException $err){
   
    echo '<pre>';
    // echo json_encode($err);
    echo '出现了错误:'.$err->getMessage();//
}
?>

出现了错误:SQLSTATE[HY000] [1044] Access denied for user 'Hunter'@'localhost' to database 'beixdi'

老师为什么我这里没有报你那个错，他没告诉我是没有beixdi这个数据库的问题

WEB前端全系列/第五阶段：前后端交互/PHP、数据库编程与设计 41楼

老师你好，就是转化成json格式的时候会报这种错误，说是无效的，不转化的时候一切正常

WEB前端全系列/第五阶段：前后端交互/网络请求AJAX 42楼

链接打不开啊

WEB前端全系列/第五阶段：前后端交互/网络请求AJAX 43楼

老师为什么结果总是操作失败执行不了sql语句

WEB前端全系列/第五阶段：前后端交互/PHP、数据库编程与设计 44楼

<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Update</title>
    <script src="./jquery-3.6.0.min.js"></script>
</head>

<body>
    <input type="text"><button>提交</button>
</body>
<script>
    var button = document.querySelector("button");
    button.addEventListener("click", function() {
        var addedAge = document.querySelector("input").value;
        $.ajax({
            type: 'get',
            url: "http://localhost/allSim/setAddedAge.php",
            data: {
                addedAge: addedAge
            },
            success: function(data) {
            console.log(data);
                /*data = JSON.parse(data) ;*/
                if (data.msg) {
                    console.log(data.msg);
                } else {
                    console.log(data);
                }
            }
        });
    })
</script>

</html>

php:

<?php

$addedAge=$_get["addedAge"];

$con=mysqli_connect("localhost","root",'','sim4_history_saves_sim');

if($con){

mysqli_query($con,"set names utf8");

$sql="update gameupdateddata set value=$addedAge where item=addedAge" ;

$result=mysqli_query($con,$sql);

if($result->num_rows>0){

$data=mysqli_fetch_all($result,MYSQLI_ASSOC);

mysqli_close($con);

echo json_encode($data);

}else{

echo json_encode(array("msg"=>"查询结果不存在"));

}

}else{

echo json_encode(array("msg"=>"数据库连接错误！"));

}

我想实现一个改数据的功能

html文件是一个输入框和按钮，输入要改的值，点击按钮，更改数据库的值

数据库的值没有被改,我把data打印出来是

Warning: Undefined variable $_get in C:\xampp\xampp\htdocs\allSim\setAddedAge.php on line 2

Warning: Trying to access array offset on value of type null in C:\xampp\xampp\htdocs\allSim\setAddedAge.php on line 2

Fatal error: Uncaught mysqli_sql_exception: 由于目标计算机积极拒绝，无法连接。 in C:\xampp\xampp\htdocs\allSim\setAddedAge.php:3

Stack trace:

#0 C:\xampp\xampp\htdocs\allSim\setAddedAge.php(3): mysqli_connect('localhost', 'root', '', 'sim4_history_sa...')

#1 {main}

thrown in C:\xampp\xampp\htdocs\allSim\setAddedAge.php on line 3

update.html:31