空白的PHP屏幕——用表单更新数据库 - Blank PHP Screen -- Updating Database with a Form

Blank PHP Screen -- Updating Database with a Form

我是新手，所以请原谅我。我试图使一个页面，一个登录的用户可以在数据库中更新他们的行信息。我在这里坐了几个小时想弄明白，也许有人能帮我弄明白。现在我甚至得到一个空白页，不知道为什么。

   <?php
require_once('auth.php');
require_once('config.php');
$errmsg_arr = array();
$errflag = false;
//Connect to mysql server
$conn = mysql_connect(DB_HOST, DB_USER, DB_PASSWORD);
if(!$conn) {
    die('Failed to connect to server: ' . mysql_error());
    }
    //Select database
$db = mysql_select_db(DB_DATABASE);
if(!$db) {
    die("Unable to select database");
}
//Create query
$qry="SELECT * FROM members WHERE member_id='" . $_SESSION['SESS_MEMBER_ID'] . "'";
$result=mysql_query($qry);
//Check whether the query was successful or not
if($result) {
    if(mysql_num_rows($result) == 1) {
        session_regenerate_id();
        $member = mysql_fetch_assoc($result);
        $_SESSION['SESS_MEMBER_ID'] = $member['member_id'];
        $_SESSION['SESS_FIRST_NAME'] = $member['firstname'];
        $_SESSION['SESS_LAST_NAME'] = $member['lastname'];
        $_SESSION['SESS_EMAIL'] = $member['email'];
        session_write_close();
        //header("location: index.php");
        exit();
    }
}else {
    die("Query failed");
}
    ?>

然后我试图在我的表单中显示查询的结果，我已经在框中创建了默认值。据我所知，应该是这样的?

    <input name="fname" type="text" class="textfield" id="fname" value="<?php echo $member['member_id'] ?>"/>

我想从那里传递新的数据，这样我就可以写更新sql语句。

或者，如果你有什么资源可以帮助我以一种简单的方式解释它，我将非常感激。

查询成功后调用exit()。如果您继续显示结果，您的脚本将已经终止。

    $_SESSION['SESS_MEMBER_ID'] = $member['member_id'];
    $_SESSION['SESS_FIRST_NAME'] = $member['firstname'];
    $_SESSION['SESS_LAST_NAME'] = $member['lastname'];
    $_SESSION['SESS_EMAIL'] = $member['email'];
    //header("location: index.php");
    // Don't call exit()!
    // Remove this!
    exit();