Let's learn php7 to connect to MySQL and create a simple query program

Simple Tutorial
Assume that we are making a class status inquiry program and will use PHP7 environment to connect in the form of PDO MySQL.
Check your class by student number and name.
Let’s first introduce the file structure and database structure:
PHP:
config.php stores database configuration information
cx.php query program
index.html user interface
Recommended (free): PHP7

The structure is as shown

MySQL:
table Name: data
Field: 1.Sid 2.name 3.class

The structure is as shown in the figure

Ready, let’s start, now!
First build the user interface (index.html), two simple edit boxes and a simple button:

nbsp;html>
    <meta>
    <title>分班查询系统</title>

    

学号:

    

姓名: 

    

Okay, let’s configure the database information (config.php)

<?php $server="localhost";//主机的IP地址$db_username="root";//数据库用户名$db_password="123456";//数据库密码$db_name = "data";

Then write our main program (cx.php)

<?phpheader ("Content-Type: text/html; charset=utf8");if(!isset($_POST["submit"])){
    exit("未检测到表单提交");}//检测是否有submit操作include ("config.php");$Sid = $_POST[&#39;Sid&#39;];//post获得学号表单值$name = $_POST[&#39;name&#39;];//post获得姓名表单值echo "<table style=&#39;border: solid 1px black;&#39;>";echo "<tr>
<th>学号</th>
<th>姓名</th>
<th>班级</th>
</tr>";class TableRows extends RecursiveIteratorIterator{
    function __construct($it)
    {
        parent::__construct($it, self::LEAVES_ONLY);
    }

    function current()
    {
        return "<td>" . parent::current() . "</td>";
    }

    function beginChildren()
    {
        echo "<tr>";
    }

    function endChildren()
    {
        echo "</tr>" . "\n";
    }}try {
    $conn = new PDO("mysql:host=$server;dbname=$db_name", $db_username, $db_password);
    $conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
    $stmt = $conn->prepare("SELECT Sid, name, class FROM data where Sid=$Sid and name='$name'");
    $stmt->execute();

    // 设置结果集为关联数组
    $result = $stmt->setFetchMode(PDO::FETCH_ASSOC);
    foreach (new TableRows(new RecursiveArrayIterator($stmt->fetchAll())) as $k => $v) {
        echo $v;
    }} catch (PDOException $e) {
    echo "Error: " . $e->getMessage();}$conn = null;echo "";

This program is finished
Let’s give it a try

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